Microemulsion compositions

ABSTRACT

Provided are oil-in-water microemulsions for formulating pharmaceutically active compounds. The microemulsions contain oils, surfactants, water, and the pharmaceutical compounds, and are produced by mixing an aqueous phase and a lipid phase in which each phase contains at least one surfactant in a defined ratio whereby the resulting microemulsion has very small dispersed particles, and, is thermodynamically very stable.

RELATED APPLICATIONS

This application is a continuation of International PCT application No.PCT/IT2019/000048, entitled “Microemulsion Compositions,” filed Jun. 11,2019, to inventors Elena Solfato, Ilenia Abbate, Cristina Maria ConcettaZappulla, Manuela Santonocito, Santa Viola, Sandro De Falco, andFrancesco Giuliano, and Applicants SIFI S.p.A. and Consiglio Nazionaledelle Ricerche. The subject matter of this application is incorporatedby reference in its entirety.

FIELD

Provided are oil-in-water microemulsions for formulating pharmaceuticalcompositions. The microemulsions contain dispersed particles of asize<30 nm. The microemulsions are advantageous for ophthalmicindications.

BACKGROUND

Pharmaceutically active substances useful for therapeutic applicationsgenerally are poorly soluble as well as unstable in aqueous solutions.Often these substances have been formulated in emulsions. One of thefirst examples of exploiting microemulsions for producing supply systemsfor poorly soluble active ingredients in the field of ophthalmology isrepresented by the work of Siebenbrodt and Keipert (Siebenbrodt I,Keipert S, Poloxamer-Systems as Potential Ophthalmics—II.Microemulsions, Eur. J. Pharm. Biopharm, 1993, 39:25-30). The authorsstudied microemulsions based on a nonionic polymeric surfactant(poloxamer) and propylene glycol as a co-surfactant in a triacetinsolution, with poorly water-soluble ingredients, such as activeingredients (indomethacin, diclofenac sodium and chloramphenicol) andwater, obtaining spontaneous stable microemulsions, for surfactantconcentrations of 15% and concentrations of propylene glycol of 40%.

Many emulsions, however, are not stable and/or have low bioavailabilityof the active substances. Formulations of active substances that arecharacterized by chemical stability, biological safety, and advantageousbioavailability profiles are needed.

SUMMARY

Provided are oil-in-water microemulsions for formulatingpharmaceutically active compounds, particularly those with low aqueoussolubility. The emulsions, which can be formulated for administrationvia a variety of routes and for a variety of uses, are particularlyadvantageous for ophthalmic applications. Also provided are theemulsions containing pharmacologically active ingredients. Themicroemulsions provided herein have elevated stability, which allowslong-term preservation, including at room temperature. Where theincorporated active ingredient is relatively unstable, the formulationin the microemulsion allows its structural integrity to be prolonged intime. The emulsions herein not only have enhanced stability, but alsoconfer enhanced bioavailability of poorly water-soluble drugs in aliquid dosage form.

Hence, provided are microemulsions for administration of anypharmaceutically active compound, particularly those not soluble inaqueous compositions. The microemulsions can be prepared to beadministered by any route, including oral and parenteral, and areparticularly suited for administration of active compounds to the eye,and include ophthalmic compounds, for treatment of disorders, such asdry eye and age-related macular degeneration (AMD). The microemulsionsare prepared by combining particular ratios of surfactants in theaqueous and lipid (lipophilic) phases, generally, but not limited to,two surfactants (a surfactant and co-surfactants) in each phase. Whenthe aqueous and lipophilic phases are combined, the resultingmicroemulsion forms. The resulting microemulsion has very smallparticles, less than 30 nm on average, generally less than or equal to15 nm, and a very narrow distribution of particle sizes, generally about15±10 nm. Among the resulting properties of the emulsions are increasedthermal stability and high bioavailability of any agent formulated inthe emulsions compared to similar emulsions in the prior art.

Microemulsions provided herein are produced from: a lipid phasecontaining an oily (oil) component and surfactant(s) andco-surfactants(s); and an aqueous phase, also containing surfactant(s)and co-surfactants(s). To achieve the advantageous properties, includingthe small particle size, the following criteria are required:

1) when forming the microemulsions, the weight/volume ratio between thesurfactants/co-surfactants in the lipid phase and thesurfactants/co-surfactants in the aqueous phase, is from 2 to 10, suchas 2.2 to 9.8 or 2.4 to 8.6; and

2) the weight/volume ratio between the oily (oil) component of the lipidphase and the surfactants/co-surfactants in the aqueous phase is from0.2 to 1.0, such as 0.22 to 0.98 or 0.24 to 0.96; and

3) in the lipid phase, the weight/volume ratio between the oily (oil)component and the mixture of the surfactants/co-surfactants in the lipidphase is from 0.05 to 1.4, such as 0.07 to 1.2 or 0.1 to 1.

When at least 1) and 2) of these criteria are met, the resultingmicroemulsion exhibits the advantageous properties, including the smallparticle size and the resulting high thermodynamic stability.

The microemulsions are used for formulating active substances, such asactive small molecule drugs, for ophthalmic indications. Themicroemulsions also can be used to formulate active substances for oraladministration or other routes of administration.

The surfactants/co-surfactants all can be the same, so that theresulting microemulsion contains a single surfactant. Generally,however, in preparing the microemulsions, each phase will contain atleast one surfactant, and one co-surfactant that is different from thesurfactant. Both phases can contain the same surfactant andco-surfactant so that the resulting microemulsion has one surfactant andone co-surfactant. In other embodiments, two or three of thesurfactants/co-surfactants can be the same in the lipid phase andaqueous phase, so that the resulting microemulsion contains two or threedifferent surfactants, or all can be different, so the resultingmicroemulsion contains four different surfactants. The microemulsionscan contain more than one surfactants and one co-surfactants in eitherphase when producing the microemulsions. Thus, two or three of thesurfactants/co-surfactants can be the same in the lipid phase andaqueous phase, so that the resulting microemulsion contains two or threedifferent surfactants, or all can be different, so the resultingmicroemulsion contains four different surfactants. The microemulsionscan contain more than two surfactants/co-surfactants in either phasewhen producing the microemulsions.

The surfactant(s)/co-surfactant(s) can be different for the two phasesso that, in a first instance, the resulting microemulsion can contain aminimum of one co-surfactant, the same for both phases, and a differentsurfactant for each of the two phases. In a second instance the lipidphase can contain two different surfactants, one of which can be thesame as the one contained in the aqueous phase. Thus, for example thecomponent surfactants and co-surfactants can be:

Instance Surfactant Co-surfactant Phase 1 S1 COS Lipidic — S2 COSAqueous 2 S1 S2 COS Lipidic — S2 COS AqueousSee also Table 1 below.

To produce the microemulsions with the properties described herein, theamounts of surfactant and co-surfactant must adhere to the ratios asdescribed herein. It is the recited ratios, particularly 1) and 2), asset forth above, that result in a microemulsion with the advantageousproperties, including small particle size and narrow particle sizedistribution. The surfactants/co-surfactants generally are nonionicsurfactants that are biocompatible and amenable to introduction into theeye.

In an exemplary embodiment, the microemulsion is composed of 0.4-4.0%(w/v) of an oily component, such as a natural vegetable oil, from thelipid phase, surfactants/co-surfactants from the lipid phase of4.0%-36.0% (w/v) of the resulting microemulsion, andsurfactants/co-surfactants from the aqueous phase of 1.66%-4.15% (w/v)of the resulting microemulsion. The remaining components of thecomposition are polar or aqueous ingredients, such as water, an activecompound(s), and other components included in pharmaceuticalcompositions, such as thickeners, such as gums, tonicity adjusters, anda biocompatible acid to adjust the pH to about or between 5.0 and 8,inclusive, such as pH 5.4 or 7.5, or 6 to 7. The active ingredient canbe included up to about 5% w/v (from 0.001 mg/ml to 50 mg/ml) of theresulting microemulsion.

Provided are pharmaceutical compositions that are microemulsions andcontain active ingredients, such as a pharmaceutical agent that ispoorly soluble in aqueous medium. The pharmaceutically active compoundsinclude those for ophthalmic use. The amount of active compound dependsupon the compound, and indication for which it is used. Exemplary of therange is 0.001 mg/ml to 50 mg/ml, or 0.01 mg/ml to 50 mg/ml, such as0.01 mg/ml to 30 mg/ml.

The pharmaceutical composition contains: a) a lipid phase comprising anoily component and one or more surfactant(s) and, one or moreco-surfactant(s), and b) an aqueous phase comprising one or moresurfactant(s), and one or more co-surfactants, where: the weight/volumeratio between the amount of surfactant and co-surfactant in the lipidphase to the amount of surfactant and co-surfactant in the aqueous phaseis from 2 to 10; the weight/volume ratio between the amount of oilcomponent in the lipid phase to the amount of surfactant(s) andco-surfactant(s) in the aqueous phase is from 0.2 to 1.0; and in theresulting oil-in-water microemulsion, the average particle size is lessthan 30 nm. The composition optionally contains active ingredient, suchas an active ingredient for ophthalmic use. By virtue of the ratios andthe surfactant(s)/co-surfactant(s) in each phase, the resultingmicroemulsion composition has a narrow size distribution; generally thesize distribution of particles in the resulting microemulsion is 15nm±10 nm. The polydispersity index (PDI) is within the range 0.02-0.380,inclusive, or 0.02 to 0.2, inclusive, or 0.02 to 0.15, inclusive, or isless than 0.2 or less than 0.12 or less than 0.1. In some embodiments,the weight/volume ratio between the amount of surfactant andco-surfactant in the lipid phase to the amount of surfactant andco-surfactant in the aqueous phase is 2.2 to 9.8, inclusive, or 2.4 to8.6, inclusive. In some embodiments, the weight/volume ratio between theamount of oil component in the lipid phase to the amount ofsurfactant(s) and co-surfactant(s) in the aqueous phase is from 0.22 to0.98, inclusive or from 0.24 to 0.96, inclusive. In some embodiments,the weight/volume ratio between the oily component and the surfactant(s)and co-surfactant(s) is from 0.05 to 1.4, inclusive, such as, forexample, from 0.07 to 1.2, inclusive, or from 0.1 to 1, inclusive.

Exemplary of these microemulsion compositions is one that contains: anoil component in an amount that is between 0.4%-4.0% (w/v), inclusive,of the composition; surfactant(s) and co-surfactant(s) of the lipidphase in an amount that is between 4.0%-36.0% (w/v), inclusive, of thecomposition; and surfactant(s) and co-surfactant(s) of the aqueous phasein an amount that is between 1.66%-4.15% (w/v), inclusive, of thecomposition.

Provided are oil-in-water microemulsion compositions, comprising: an oilcomponent in an amount of 0.4-4.0% weight/volume (w/v) of thecomposition; a surfactant or a mixture of a surfactant(s) andco-surfactants(s) in an amount of 5.71-40.15% (w/v), inclusive, of thecomposition; an aqueous component that is in an amount between55.85%-93.89% (w/v), inclusive, of the composition; and optionally apharmaceutically active compound, where: all components of thecomposition are biocompatible; and the average particle size in themicroemulsion composition is less than 30 nm. As above, the distributionof particle size is narrow, generally 15 nm±10 nm. The polydispersityindex (PDI) is within the range 0.02-0.380, inclusive, or 0.02 to 0.2,inclusive, or 0.02 to 0.15, inclusive, or is less than 0.2 or less than0.12 or less than 0.1. The oil-in-water microemulsions can contain apharmaceutically active compound. The amount of pharmaceutically activecompound can depend upon the compound and indication for which it isintended. Generally, the concentration is 0.001 mg/ml to 50 mg/ml, or0.01 mg/ml to 50 mg/ml, or 0.01 mg to 50 mg/ml, such as 0.01 mg/ml to 30mg/ml.

The oil-in-water microemulsion compositions are formed from: a lipidphase comprising the oily component, and one or more surfactant(s), andoptionally one or more co-surfactants(s); and an aqueous phasecomprising one or more surfactant(s), and one or more co-surfactants(s),where: the weight/volume ratio between surfactant(s) andco-surfactants(s) in the lipid phase to surfactant(s) andco-surfactants(s) in the aqueous phase is from 2 to 10, inclusive; andthe weight/volume ratio between the oily component of the lipid phaseand the surfactant(s) and co-surfactants in the aqueous phase is from0.2 to 1.0, inclusive. In some embodiments, the weight/volume ratiobetween surfactant(s) and co-surfactants(s) in the lipid phase to thesurfactant(s) and co-surfactants(s) in the aqueous phase is 2.2 to 9.8,inclusive, or 2.4 to 8.6, inclusive; and the weight/volume ratio betweenthe oily component in the lipid phase and the surfactant(s) andco-surfactants in the aqueous phase is from 0.22 to 0.98, inclusive, orfrom 0.24 to 0.96, inclusive. In other embodiments, in the lipid phase,the weight/volume ratio between the oily component and the surfactant(s)and co-surfactants(s) is from 0.05 to 1.4, inclusive, such as, forexample, from 0.07 to 1.2, inclusive, or from 0.1 to 1, inclusive.Generally each phase contains one surfactant and one co-surfactant. Uponmixing in the ratios described herein, they form a microemulsion inwhich the average particle size is less than 30 nm. Generally theparticles have a narrow size distribution of 15 nm±10 nm. The resultingmicroemulsions have a polydispersity index (PDI) generally within therange 0.02-0.380, inclusive, or 0.02 to 0.2, inclusive, or 0.02 to 0.15,inclusive, or is less than 0.2 or less than 0.12 or less than 0.1.Compositions provided herein include those where the micellar dimensionof the dispersed phase particles is approximately or is 15±10 nm; andthe polydispersity index (PDI) is within the range 0.02-0.380,inclusive, or 0.02 to 0.2, inclusive, or 0.02 to 0.15, inclusive, or isless than 0.380, or is less than 0.2 or less than 0.12 or less than 0.1.

All of the compositions provided herein can be used for formulation ofpharmaceutical agents for treatment of diseases and disorders, such asophthalmic conditions or disorders. For ophthalmic use, the ingredientsshould be selected to be compatible with or suitable for administrationto the eye. In the compositions, each of the surfactant(s) and/orco-surfactant(s) can be nonionic. In all of the compositions the HLB ofeach of the surfactants and co-surfactants can be between 8-16,inclusive, such as where the HLB of each of the surfactants andco-surfactants is at least 10, such as 10-16, or 12-14. In someembodiments, the compositions contain one surfactant and aco-surfactant, or two surfactants and one co-surfactant, or twosurfactants and two co-surfactants. In some embodiments, thecompositions are formed from a lipid and aqueous phase in which thesurfactant is the same so that the resulting microemulsion contains onesurfactant, and generally one or two co-surfactants. In otherembodiments, the surfactant in each phase is different. In someembodiments, the compositions are formed from a lipid and aqueous phasein which the aqueous phase contains a surfactant and a co-surfactant,and the lipid phase contains a surfactant and a co-surfactant. Theco-surfactant in each phase can be the same or different.

In general, each phase from which the microemulsion is formed containsone surfactant and one co-surfactant. The surfactants and co-surfactantscan be the same or different. For example, in one embodiment the lipidphase contains Tween 80/propylene glycol as thesurfactant/co-surfactant, and the aqueous phase contains KolliphorRH40/propylene glycol.

Surfactants can be selected from among, for example, poloxamers,PEGylated fatty acids, polyoxyethylene sorbitan fatty acid derivatives,polyoxyethylenes, hydrogenated castor oil ethoxylates, glycerol estersof fatty acids, polyoxyl castor oil surfactants, amine oxides, andalcohol ethoxylates (nonionic). Exemplary of these are polyethyleneglycol sorbitan monolaurate (polysorbate 20; TWEEN 20), polyethyleneglycol sorbitan monooleate (polysorbate 80; TWEEN 80), and polyethyleneglycol sorbitan monopalmitate (polysorbate 40; MONTANOX 40. In otherembodiments the surfactants are selected from among polyoxyl 35 castoroil (CREMOPHOR EL, KOLLIPHOR EL), polyoxyl 40 hydrogenated castor oil(CREMOPHOR RH40; KOLLIPHOR RH 40), PEG 40 castor oil (ETOCAS 40), PEG-60hydrogenated castor oil (CRODURET 60), and polyethylene glycol15-hydroxystearate (KOLLIPHOR HS 15).

The surfactants can be nonionic. For example, nonionic surfactants canbe selected from among Pluronic®, Cremophor®, Kolliphor®, Polysorbates(Tween™), lauryl dimethyl ammine oxide, polyethoxylated alcohol,polyoxyl lauryl ether, Brij®, polyoxyethylated castor oil, lecithin,poloxamers, polyethylene glycol, glycerol esters of fatty acids. In someembodiments the surfactants are selected from among castor oil orhydrogenated castor oil ethoxylates. Co-surfactants include glyceroland/or propylene glycol. For example, each phase can include the same ordifferent co-surfactant.

The lipid phase contains an oil, which can be selected from among one ormore of vegetable or animal oils or synthetic mineral oils. In someembodiments the oils are vegetable or animal oils selected from amongsoya oil, corn oil, linseed oil, sunflower seed oil, krill oil,cod-liver oil, fish oil, avocado oil, almond oil, babassu oil, borageoil, carob oil, cashew nut oil, grapeseed oil, coconut oil, Oryza sativabran oil, castor oil, hemp seed oil, jojoba oil, peanut oil, poppy seedoil, sesame oil, walnut oil, olive oil, wheat-germ oil, argan oil,cottonseed oil, blackcurrant seed oil, and oils rich in PUFAs by afraction greater than 10%. In other embodiments the oil can be a mineraloil of synthetic origin selected from esters of medium and long-chainfatty acids, and medium and long-chain triglycerides.

Other ingredients in the compositions include one or more of anisotonizing (tonicity) agent, stabilizing agent, anti-oxidant,anti-microbial, thickening agent, and branched and linear polymers.

The compositions can contain one or more pharmaceutically activeingredients. The one or more active ingredients are present at asuitable concentration for use or storage. Concentration ranges include,but are not limited to, from 0.01 to 50 mg/ml, inclusive, or 0.01 to 30mg/ml.

The compositions can be formulated with the pharmaceutically activeingredient, in the lipid phase, if the ingredient is non-polar, or inthe aqueous phase, if it is polar. Exemplary of the pharmaceuticallyactive ingredients are one or more gastrointestinal agents,antispasmodics, blood sugar regulators,nutraceuticals/minerals/electrolytes, platelet modifying agents,coagulants, cardiovascular agents, alpha-adrenergicagonists/alpha-adrenergic antagonists/vasodilators/arterialvasodilators, carbonic anhydrase inhibitor diuretics/loopdiuretics/potassium-sparing diuretics/thiazide diuretics, othercardiovascular agents, beta-adrenergic antagonists, calcium channelblockers, angiotensin converting enzyme inhibitors (ACE),dyslipidemics/HMG CoA Reductase inhibitors (Statins), anti-fungals,dermatological agents, anti-histamines, anesthetics, anti-bacterials,hormone-stimulating agents/substituents/modifiers (adrenals, pituitaryand sex hormones), glycemic agents, hormone-suppressing agents(parathyroids), anti-mycobacterials, anti-virals, anti-neoplastics,immunomodulators, anti-inflammatory agents, analgesics,anti-convulsants, anti-Parkinson agents, anti-psychotics,anti-depressants/anti-dementia agents/anti-anxiety medication,anti-myasthenic agents/agents for treating substances of abuse/centralnervous system agents,bronchodilators/sympathomimetics/anti-cholinergics/inhaledcorticosteroids/phosphodiesterase inhibitors/airborne disorders, otheragents of the respiratory tract, anti-parasites, anti-glaucomaophthalmic agents, other ophthalmic agents/anti-allergic ophthalmicagents, ophthalmic anti-inflammatories, prostaglandin analogues andophthalmic prostamides, drugs for acidity-related disorders (A02), drugsfor gastrointestinal function disorders (A03), drugs used for diabetes(A10), vitamins (A11), mineral supplements (A12), antithrombotic agents(B01), anti-hemorrhagics (B02), cardiac therapy drugs (C01),anti-hypertensives (C02), diuretics (C03), peripheral vasodilators(C04), vasoprotectives (C05), beta-blocking agents (C07),calcium-antagonists (C08), drugs acting on the renin-angiotensin system(C09), lipid-lowering drugs (C10), anti-fungals for dermatological use(D01), emollients and protectives (D02), drugs for injuries and ulcers(D03), antipruritics, including anti-histamines, anaesthetics (D04),anti-psoriasis drugs (D05), antibiotics and chemotherapeutic agents fordermatological use (D06), antiseptics and disinfectants (D08),hyphophyseal, hypothalamic hormones and similar (H01), systemiccorticosteroids (H02), thyroid therapy (H03), pancreatic hormones (H04),homeostatic calcium (H05), anti-bacterials for systemic use (J01),anti-mycotics for systemic use (J02), anti-mycobacterials (J04),anti-viral drugs for systemic use (J05), immune serums andimmunoglobulins (J06), anti-neoplastic agents (L01), endocrine therapy(L02), immunostimulants (L03), immunosuppressants (L04),anti-inflammatories and anti-rheumatics (M01), topical products forjoint and muscle pain (M02), anesthetics (N01), analgesics (N02),anti-epileptics (N03), anti-parkinsonians (N04), psycholeptics (N05),psychoanaleptics (N06), other nervous system drugs (NO7), rhinologicpreparations (R01), preparations for the pharyngeal cavity (R02), drugsfor obstructive disorders of the respiratory tract (R03), preparationsfor coughs and colds (R05), anti-histamines for systemic use (R06),other preparations for the respiratory system (R07), anti-infectives(S01A), anti-inflammatory agents (S01B), anti-inflammatory agents andanti-infectives combined (S01C), anti-glaucoma agents and miotics(S01E), mydriatics and cyclopegics (S01F), decongestants andanti-allergens (S01G), local anaesthetics (S01H), diagnostic agents(S01J), surgical aids (S01K), ocular vascular agents (S01L),anti-infectives (S03A), corticosteroids (S03B), and corticosteroidscombined with anti-infectives (S03C).

In particular embodiments the compositions are formulated for ophthalmicadministration, and contain one or more active ingredients for treatingophthalmic conditions or disorders. Such conditions and disorders,include, but are not limited to, dry eye, macular degeneration,glaucoma, infection, inflammation, allergy and diabetic retinopathy.Exemplary of the pharmaceutically active agents is a prostaglandininhibitor, an anti-angiogenic, and/or an anti-oxidant. Such agentsinclude, a prostaglandin inhibitor selected from among latanoprost,travoprost, bimatoprost, unoprostone, and pharmaceutically acceptablederivatives, hydrates, solvates, metabolites and salts thereof, or apolymorphic crystalline form thereof, and/or an anti-angiogenic agentselected from among sorafenib, sorafenib tosylate, regorafenib,regorafenib tosylate, regorafenib isethionate, regorafenib,ethylsulfonate apremilast, radotinib, spironolactone, andpharmaceutically acceptable derivatives, hydrates, solvates, metabolitesand salts thereof, or a polymorphic crystalline form thereof; and/or ananti-oxidant selected from among nordihydroguaiaretic acid,meso-nordihydroguaiaretic (masoprocol) and pharmaceutically acceptablederivatives, hydrates, solvates, metabolites and salts thereof, or apolymorphic crystalline form thereof.

The compositions can be used for methods of treatment of diseases anddisorders by administering the composition by a suitable route. Thecompositions provided herein can be used for treating ophthalmicdisorders. Provided are methods of treatment of an ophthalmic disorderby administering a composition to the eye. Ophthalmic disorders orconditions, include, but are not limited to, dry eye, maculardegeneration, glaucoma, infection, inflammation, allergy and diabeticretinopathy. Pharmaceutical agents for such uses include, for example,masoprocol, sorafenib tosylate, and latanoprost.

Methods for preparing the microemulsion compositions are provided. Onemethod includes the steps of: a) preparing the lipid phase, where amixture of surfactants/co-surfactants is solubilized in oil, mixing from1 to 10 parts of the mixture for each oil part; b) preparing the aqueousphase, where one or more of a surfactant and/or co-surfactants issolubilized in water; c) titrating the lipid phase with the aqueousphase to obtain microemulsion, where: 0.4%-4.0% (w/v) of themicroemulsion is composed of the oil component of the lipid phase;4.0%-36.0% (w/v) of the microemulsion is composed of thesurfactants/co-surfactants of the lipid phase; and 1.66%-4.15% (w/v) ofthe total surfactants/co-surfactants are the surfactants/co-surfactantsof the aqueous phase. In another method the steps include: a) preparingthe lipid phase, which can include a pharmaceutically active agent, andin which a mixture of surfactants/co-surfactants is solubilized in oil,mixing from 1 to 10 parts of the mixture for each oil part; b) preparingthe aqueous phase, where one or more of a surfactant and/orco-surfactants is solubilized in water; c) titrating the lipid phasewith the aqueous phase to obtain a microemulsion, where: 0.4-4.0% (w/v)of the microemulsion is composed of the oily component of the lipidphase; 4.0%-36.0% (w/v) of the microemulsion is composed of thesurfactants/co-surfactants of the lipid phase, and 1.66%-4.15% (w/v) ofthe microemulsion is composed of surfactants/co-surfactants of theaqueous phase. The pharmaceutically active agent is included in anamount of at or about 0.001 mg/ml to 50 mg/ml, or 0.01 mg/ml to 50mg/ml, such as 0.01 mg/ml to 30 mg/ml of the final composition.

Pharmaceutically active agents included or added to the compositionsinclude any suitable for treatment of a particular disorder, includingany listed herein above and below. In accord with the methods, titrationrate is described by the following equation:V_(tit)=k×(v_(tot)/_(1000 ml)), where V_(tit)=titration speed inml×min-1, k=2 ml×min-1, and V_(tot)=total volume of the formulation inml. The resulting microemulsion compositions are those in which thedispersed particles in the resulting microemulsion have an average size30 nm, generally a size distribution of the particles is 15 nm±10 nm,and/or a polydispersity index (PDI) is less than 0.380, or is within therange of 0.01-0.380, inclusive, or 0.01-0.20, inclusive, or 0.01 to0.15, inclusive, or less than 0.2 or 0.1. Provided are microemulsioncompositions prepared by any of the methods described above or below.

In other methods, the microemulsion compositions are prepared by amethod that includes: a) preparing a lipid phase comprising an oilcomponent and one or more surfactant(s) and, one or moreco-surfactant(s), and b) an aqueous phase comprising one or moresurfactant(s), and one or more co-surfactants, where: the weight/volumeratio between the amount of surfactant and co-surfactant in the lipidphase to the amount of surfactant and co-surfactant in the aqueous phaseis from 2 to 10; the weight/volume ratio between the amount of oilcomponent in the lipid phase to the amount of surfactant(s) andco-surfactant(s) in the aqueous phase is from 0.2 to 1.0; and, then c)combining the lipid phase with the aqueous phase to form an oil-in-watermicroemulsion in which the average particle size is less than 30 nm.Step c) can be effected by titrating the lipid phase with the aqueousphase, where the titration rate is described by the following equation:V_(tit)=k×(v_(tot)/_(1000 ml)), where V_(tit)=titration speed inml×min-1, k=2 ml×min-1, and V_(tot)=total volume of the formulation inml.

In these methods, the weight/volume ratio between the amount ofsurfactant and co-surfactant in the lipid phase to the amount ofsurfactant and co-surfactant in the aqueous phase is 2.2 to 9.8,inclusive, or 2.4 to 8.6, inclusive.

The aqueous phase can contain one surfactant and one co-surfactant. Insome embodiments the weight/volume ratio between the amount of oilcomponent in the lipid phase to the amount of surfactant(s) andco-surfactant(s) in the aqueous phase is from 0.22 to 0.98, inclusive orfrom 0.24 to 0.96, inclusive. In other embodiments, in the lipid phase,the weight/volume ratio between the oily component and the surfactant(s)and co-surfactant(s) is from 0.05 to 1.4, inclusive. In otherembodiments in the lipid phase, the weight/volume ratio between the oilycomponent and the surfactant(s) and co-surfactant(s) is from 0.07 to1.2, inclusive, or from 0.1 to 1, inclusive. The size distribution ofparticles in the resulting microemulsion generally is 15 nm±10 nm, andthe polydispersity index (PDI) is within the range 0.02-0.380,inclusive, or 0.02 to 0.2, inclusive, or 0.02 to 0.15, inclusive, or isless than 0.2 or less than 0.12 or less than 0.1. Microemulsioncompositions prepared by any of the methods described herein areprovided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of the microemulsion platformprovided herein.

FIG. 2 depicts a diagram of the process for preparing the microemulsionsprovided herein.

FIGS. 3A-3D depict stability data after stress tests carried out onillustrative formulations of the microemulsions provided herein. Forexample, FIG. 3A shows the pH data. FIG. 3B depicts the osmolality. FIG.3C depicts the average particle distribution (size). FIG. 3D depicts theZeta potential (pZ).

FIGS. 4A and 4B depict the average particle distribution diagrams forformulations 1-(A) and 5-(B). FIG. 4A depicts the average particledistribution diagram for formulation 1-(A). FIG. 4B depicts the averageparticle distribution diagram for formulation 5-(B).

FIGS. 5A-5D depict the stability data at 6 months of an illustrativeformulation of the microemulsions provided herein. For example, FIG. 5Ashows the osmolality data. FIG. 5B depicts the pH data. FIG. 5C depictsthe average particle distribution (size). FIG. 5D depicts the Zetapotential (pZ).

FIGS. 6A-6C depict the stability data of the average particledistribution (size) and the polydispersity index (PDI) at differenttemperatures, and at different times, of an illustrative formulation ofthe microemulsions provided herein. FIG. 6A depicts the stability dataat 25° C. FIG. 6B depicts the stability data at 40° C. FIG. 6C depictsthe stability data at 60° C.

FIGS. 7A-7D depict the stability data after stress tests carried out onillustrative formulations of the microemulsions provided herein. Forexample, FIG. 7A shows the pH data. FIG. 7B depicts the average particledistribution (size). FIG. 7C depicts the polydispersity index (PDI).FIG. 7D depicts the Zeta potential (pZ).

FIGS. 8A-8E depict the stability data after stress tests carried out onillustrative formulations of the microemulsions provided herein. Forexample, FIG. 8A shows the pH data. FIG. 8B depicts the average particlesize (size). FIG. 8C depicts the polydispersity index (PDI). FIG. 8Ddepicts the osmolality. FIG. 8E depicts the Zeta potential (pZ).

FIGS. 9A-9E depict the stability data after stress tests carried out onillustrative formulations of the microemulsions that contain an activeingredient, such as latanoprost. For example, FIG. 9A shows the pH data.FIG. 9B depicts the osmolality. FIG. 9C depicts the average particledistribution (size). FIG. 9D depicts the Zeta potential (pZ). FIG. 9Edepicts the recovery.

FIGS. 10A-10E depict the stability data at 24 months of an illustrativeformulation of the microemulsions that contain an active ingredient,such as latanoprost. For example, FIG. 10A shows the pH data. FIG. 10Bdepicts the osmolality. FIG. 10C depicts the average particledistribution (size). FIG. 10D depicts the Zeta potential (pZ). FIG. 10Edepicts the recovery.

FIGS. 11A-11D depict the stability data of the average particledistribution (size) and the polydispersity index (PDI) at differenttemperatures, and at different times, of an illustrative formulation ofthe microemulsions that contain an active ingredient, such aslatanoprost. FIG. 11A depicts the stability data at 25° C. FIG. 11Bdepicts the stability data at 40° C. FIG. 11C depicts the stability dataat 60° C. FIG. 11D depicts the stability data at 4° C.

FIGS. 12A-12E depict the stability data at 3 and 9 months ofillustrative formulations of the microemulsion that contain an activeingredient, such as masoprocol. For example, FIG. 12A shows the pH data.FIG. 12B depicts the osmolality. FIG. 12C depicts the average particledistribution (size). FIG. 12D depicts the Zeta potential (pZ). FIG. 12Edepicts the recovery.

FIGS. 13A-13E depict the stability data at 3 months and at differentconditions, 25±2° C./60±5% RH and 40±2° C./75±5 RH, of illustrativeformulations of the microemulsions provided herein that contain anactive ingredient, such as sorafenib tosylate. For example, FIG. 13Ashows the pH data. FIG. 13B depicts the average particle distribution(size). FIG. 13C depicts the polydispersity index (PDI). FIG. 13Ddepicts the Zeta potential (pZ). FIG. 13E depicts the recovery.

FIG. 14 depicts the efficacy of microemulsion containing latanoprost0.005% (formulation 03), compared to a standard solution of latanoprost0.005% (Solution), in EVC rats treated topically (6 days, once a day, 12μl). Statistical analyses were performed using the Student t-test.

FIGS. 15A and 15B depict the gene expression of TNFa (tumor necrosisfactor-a) and iNos in IR rat retinas pretreated topically 2 days and 1 hbefore inducing IR with microemulsions alone or containing masoprocol0.302% (formulation 1, formulation 04; and formulation 6 or formulation06) and sacrificed 6 h after the ischemic episode. FIG. 15A depicts thegene expression data after pretreatment with formulation 1 orformulation 04. FIG. 15B depicts the gene expression data afterpretreatment with formulation 6 or formulation 06. The data representsthe average±SEM of the Fold Change in relation to the calibrator (CTRLNAIVE). # p≤0.05, ## p≤0.01 vs. formulation 1 (FIG. 15A) and formulation6 (FIG. 15B). *p≤0.05, ****p≤0.0001 vs. CTRL NAÏVE (FIG. 15A and FIG.15B). One-way ANOVA followed by Dunnett's post-hoc test.

FIGS. 16A and 16B depict the gene expression of TNFa and iNos in IR ratretinas pretreated topically 2 days and 1 h before inducing IR withmicroemulsions alone or containing sorafenib tosylate 0.300%(formulation 2, formulation 05; formulation 7 or formulation 07) andsacrificed 6 h after the ischemic episode. FIG. 16A depicts the geneexpression data after pretreatment with formulation 2 or formulation 05.FIG. 16B depicts the gene expression data after pretreatment withformulation 7 or formulation 07. The data represents the average±SEM ofthe Fold Change in relation to the calibrator (CTRL NAIVE). # p≤0.05, ##p≤0.01, ### p≤0.001 vs. formulation 2 (FIG. 16A) and formulation 7 (FIG.16B). *p≤0.05, ***p≤0.001, ****p≤0.0001 vs. CTRL NAÏVE (FIG. 16A andFIG. 16B). One-way ANOVA followed by Dunnett's post-hoc test.

FIG. 17 depicts an analysis of the neovascularization areas in CNV micepretreated topically for three days before inducing CNV and for thefollowing 7 days with formulation 1 or formulation 04 containingmasoprocol 0.302% (formulation 04). The data is represented as theaverage±SEM in relation to formulation 1. *p=0.0395 vs. formulation 1.Images representative of choroidal neovascularization (CNV) in animalstreated with formulation 1 or formulation 04 are shown at a side. Thescale bar represents 100 μm.

FIGS. 18A and 18B depict an analysis of the neovascularization areas inCNV mice pretreated topically for three days before inducing CNV and forthe following 7 days with microemulsions alone or containing sorafenibtosylate 0.300% (formulation 2, formulation 05; formulation 7,formulation 07). FIG. 18A depicts the data after pretreatment withformulation 2 or formulation 05.

FIG. 18B depicts the data after pretreatment with formulation 7 orformulation 07. The data is represented as the average±SEM in relationto formulation 2 (FIG. 18A) or 7 (FIG. 18B), respectively. *p=0.0135 vs.formulation 2 (FIG. 18A); *p=0.0001 vs. formulation 7 (FIG. 18B). Imagesrepresentative of CNV in animals treated with formulation 2, formulation05, formulation 7 or formulation 07 are shown at a side. The scale barrepresents 100 μm.

FIGS. 19A-19F depict the gene expression of TNFa, NFκB, IGF1, IGFR1,VEGFR1 and VEGFR2 in Ctrl-rat retinas, diabetic (STZ) and diabetictreated b.i.d. topically for 21 days with microemulsion containingmasoprocol 0.302% (formulation 04) or microemulsion containing sorafenibtosylate 0.300% (formulation 05). FIG. 19A depicts the gene expressionof TNFa. FIG. 19B depicts the gene expression of NFκB. FIG. 19C depictsthe gene expression of IGF1. FIG. 19D depicts the gene expression ofIGFR1. FIG. 19E depicts the gene expression of VEGFR1. FIG. 19F depictsthe gene expression VEGFR2. The data represents the average±SEM of theFold Change in relation to the calibrator (Ctrl). *p≤0.05, **p≤0.01,***p≤0.001 vs. Ctrl-. ### p≤0.001 vs. STZ. ANOVA followed byTukey-Kramer's post-hoc test.

FIGS. 20A-20H depict the protein expression of TNFa (also referred to asTNF-alpha), VEGFR1 and VEGFR2 in Ctrl-rat retinas, diabetic (STZ) anddiabetic treated b.i.d. topically for 21 days with microemulsioncontaining masoprocol 0.302% (formulation 04) or microemulsioncontaining sorafenib tosylate 0.300% (formulation 05). FIG. 20A depictsthe protein expression of VEGF1R after treatment with microemulsioncontaining masoprocol 0.302% (formulation 04). FIG. 20B depicts theprotein expression of TNFa after treatment with microemulsion containingmasoprocol 0.302% (formulation 04). FIG. 20C depicts the proteinexpression of VEGFR2 after treatment with microemulsion containingmasoprocol 0.302% (formulation 04). FIG. 20D depicts a Western blotanalysis of TNFa, VEGFR1 and VEGFR2 in Ctrl-rat retinas, diabetic (STZ)and diabetic treated b.i.d. topically for 21 days with microemulsioncontaining masoprocol 0.302% (formulation 04). FIG. 20E depicts theprotein expression of TNFa after treatment with microemulsion containingsorafenib tosylate 0.300% (formulation 05). FIG. 20F depicts the proteinexpression of VEGFR1 after treatment with microemulsion containingsorafenib tosylate 0.300% (formulation 05). FIG. 20G depicts the proteinexpression of VEGFR2 after treatment with microemulsion containingsorafenib tosylate 0.300% (formulation 05). FIG. 20H depicts a Westernblot analysis of TNFa, VEGFR1 and VEGFR2 in Ctrl-rat retinas, diabetic(STZ) and diabetic treated b.i.d. topically for 21 days withmicroemulsion containing sorafenib tosylate 0.300% (formulation 05). Thedata represents the average±SEM. ***p<0.001 vs Ctrl-. ## p<0.01, ###p<0.001 vs. STZ. ANOVA followed by Tukey-Kramer's post-hoc test.

FIG. 21 depicts corneal damage measured by fluorescein staining at T3 indry eye mice remained untreated (CTRL+) or treated topically for 3 dayswith formulation 1 or formulation 04 containing masoprocol 0.302%(formulation 04). The scores assigned to each group are graphed as boxand whiskers bars spanning from minimum to maximum. One-way ANOVAfollowed by Dunnett's post-hoc test. **p≤0.01, ****p≤0.0001 vs. CTRL-. #p≤0.05 vs. CTRL+.

FIG. 22 depicts the gene expression of TNFa in the cornea of dry eyemice remained untreated (CTRL+) or treated topically for 3 days withformulation 1 or formulation 04 containing masoprocol 0.302%(formulation 04). The data represents the average±SEM of the Fold Changein relation to the calibrator (CTRL−). # p≤0.05 vs. CTRL+; ****p≤0.0001vs. CTRL-. One-way ANOVA followed by Sidak's post-hoc test.

DETAILED DESCRIPTION A. Definitions

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as is commonly understood by one of skill in theart to which the invention(s) belong. All patents, patent applications,published applications and publications, GenBank sequences, databases,websites and other published materials referred to throughout the entiredisclosure herein, unless noted otherwise, are incorporated by referencein their entirety. In the event that there are a plurality ofdefinitions for terms herein, those in this section prevail. Wherereference is made to a URL or other such identifier or address, it isunderstood that such identifiers can change and particular informationon the internet can come and go, but equivalent information can be foundby searching the internet. Reference there to evidences the availabilityand public dissemination of such information.

As used herein, an emulsion is a system composed of two immiscibleliquid phases, intimately mixed and dispersed, the one into the other.An emulsion refers to a colloidal dispersion of two immiscible liquids,for example, an oil and water (or other aqueous liquid, e.g., a polarsolvent), one of which is part of a continuous phase and the other ofwhich is part of a dispersed phase. The emulsions herein areoil-in-water, which include any oil soluble phase dispersed in anyaqueous phase, also called the water phase, in which the oil phase isthe dispersed phase and the water phase is the continuous phase.Emulsions typically are stabilized by one or more surfactants and/orco-surfactants and/or emulsion stabilizers. Surfactants form aninterfacial film between the oil and water phase of the emulsion,providing stability.

As used herein, a microemulsion is a two-phase systems composed of alipid phase and an aqueous phase, finely interspersed. Microemulsionsare liquid mixtures, transparent, isotropic and stable, of a lipid phaseand an aqueous phase, held together by a surfactant, generally inconjunction with a co-surfactant. Microemulsions are clear,thermodynamically stable, isotropic liquid mixtures of oil, water andsurfactant, and optionally a co-surfactant. Microemulsions formspontaneously upon mixing of the aqueous phase and lipid phase. Amicroemulsion is, therefore, a thermodynamically stable system, withparticles dispersed in the continuous phase. The droplet size of thedispersed phase in a microemulsion is less than 100 nm, generally in therange between 5 nm and 50 nm, inclusive.

As used herein, “surfactant” refer to synthetic and naturally occurringamphiphilic molecules that have hydrophobic portion(s) and hydrophilicportion(s). Surfactants contain a hydrophilic domain and hydrophobicdomain, i.e. amphiphilic molecules. Given their nature, surfactantsfacilitate the formation of oil-in-water emulsions where the micelles,in order to exist, need to interact with both the water and the oilphases. Due to their amphiphilic (amphipathic) nature, surfactants andco-surfactants can reduce the surface tension between two immiscibleliquids, for example, the oil and water phases in an emulsion, such as amicroemulsion, stabilizing the emulsion.

Surfactants can be characterized based on their relative hydrophobicityand/or hydrophilicity. For example, relatively lipophilic surfactantsare more soluble in fats, oils and waxes, typically havingHydrophobic-Lipophilic Balance (HLB) values less than 10 or about 10,while relatively hydrophilic surfactants are more soluble in aqueouscompositions, for example, water, and typically have HLB values greaterthan 10 or about 10. Relatively amphiphilic surfactants are soluble inoil and water based liquids and typically have HLB values close to 10 orabout 10. Surfactants for use in the compositions herein arebiocompatible, and have an HLB value between 8 or about 8 and 16 orabout 16, generally 10-16, or 12-14.

As used herein, a co-surfactant is a surfactant that acts in addition toanother surfactant to further reduce the surface tension of a liquid.Recitation that microemulsions contain surfactants refers to thesurfactants and the co-surfactants that are included. Co-surfactants arehydrophilic in nature, and reduce the surface tension of water. Theygenerally are used as wetting agents, for example, to increase thespreading abilities of water-based fluid by reducing the surface tensionof water. Cosurfactants also are used, and often needed, to increase thesolubility of the primary surfactant.

As used herein, “particle size” and “average particle size” refersynonymously to the average diameter of particles in a provided liquid,for example, the droplet diameter or micelle diameter in an emulsion

As used herein, “oil phase” or “lipid phase” is used to refer to theportion (or phase) of a composition such as those provided herein thatcontains one or more lipophilic ingredients and/or amphiphilicingredients, such as an oil, and is, in general, the lipid-solublephase. In an oil-in-water (o/w) microemulsion, the lipid phase typicallyis the dispersed phase while water is the dispersion phase.

As used herein, oil phase ingredient(s) refers to the components of theprovided compositions that are included in the oil phase in the providedmethods for making the compositions. Typical oil phase ingredientsinclude non-polar compounds, e.g., non-polar active ingredients; atleast one surfactant; oils, such as non-polar solvents; preservatives;and microemulsion stabilizers. Other lipophilic and/or amphiphilicingredients can be included in the oil phase.

As used herein, “water phase” or “aqueous phase” refers to the portion(phase) of a composition, such as those provided herein, that containsone or more hydrophilic ingredients and/or amphiphilic ingredients(water phase ingredients) and is, in general, the water-soluble phase.Typically, in the microemulsion compositions provided herein, the waterphase is the continuous phase. “Water phase” also is used to refer tothe liquid containing the water phase ingredients that is generatedwhile preparing microemulsions.

As used herein, water phase ingredient(s) refers to the components ofthe compositions that are included in the water phase in the providedmethods for making the compositions. Typical water phase ingredients caninclude, but are not limited to, polar solvents, typically polar proticsolvents, such as water and alcohols, typically alcohols having morethan one hydroxy group such as dihydroxy and trihydroxy alcohols, suchas glycerol and propylene glycol; at least one surfactant;preservatives; and emulsion stabilizers. Other hydrophilic and/oramphiphilic ingredients can be included in the water phase.

As used herein, thermodynamic stability of the microemulsions refers tothe stability of the dispersion such that the phases do not separate.The microemulsions provided herein exhibit high thermodynamic stabilityas shown by their stability at elevated temperatures.

As used herein, a subject includes an animal, typically a mammal,typically a human.

As used herein, room temperature and ambient temperature are used todescribe a temperature that is common in one or more enclosed spaces inwhich human beings typically are or reside. Room temperature can vary,but generally refers to temperatures between 19° C. or about 19° C. and25° C. or about 25° C. When a composition is stored at room temperature,it should be understood it is generally kept at a temperature withinthis range or about within this range.

As used herein, refrigerated temperature refers to a temperature that iscommon in a refrigerator, for example, a household or restaurantrefrigerator, for example, a temperature that is cooler than roomtemperature, but typically a few degrees above the freezing point ofwater (0° C. or about 0° C., or −19° C. or −20° C.). Typically,refrigerated temperatures are between 10° C. or about 10° C. and 0° C.or about 0° C., for example, 4° C. or about 4° C. When a composition isstored at a refrigerated temperature, it should be understood that it iskept at a temperature common to household or industrial refrigerators.

As used herein, frozen temperature refers to a temperature around orbelow the freezing point of water, e.g., a temperature commonly used ina household freezer, for example, 0° C. or about 0° C., for example,−19° C. or about −19° C. or −20° C. or about −20° C., or colder.

As used herein, the singular forms “a,” “an” and “the” include pluralreferents unless the context dictates otherwise.

As used herein, ranges and amounts can be expressed as “about” aparticular value or range. About also includes the exact amount. Hence“about 5 grams” means “about 5 grams” and also “5 grams”. It also isunderstood that ranges expressed herein include whole numbers within theranges and fractions thereof. For example, a range of between 5 gramsand 20 grams includes whole number values such as 5, 6, 7, 8, 9, 10, 11,12, 13, 14, 15, 16, 17, 18, 19 and 20 grams, and fractions within therange, for example, but not limited to, 5.25, 6.72, 8.5, and 11.95grams.

As used herein, “optional” or “optionally” means that the subsequentlydescribed event or circumstance does or does not occur and that thedescription includes instances where said event or circumstance occursand instances where it does not. For example, an optionally variantportion means that the portion is variant or non-variant. In anotherexample, an optional ligation step means that the process includes aligation step or it does not include a ligation step.

As used herein, ranges and amounts can be expressed as “about” aparticular value or range. About also includes the exact amount. Hence“about 10%” means “about 10%” and also “10%.”

As used herein, “optional” or “optionally” means that the subsequentlydescribed event or circumstance or element does or does not occur, andthat the description includes instances where said event or circumstanceor element occurs and instances where it does not. For example, anoptionally substituted group means that the group is unsubstituted or issubstituted.

B. Overview

Provided herein are thermodynamically stable microemulsions that can beused to solubilize pharmaceutically active compounds. The microemulsionsprovided herein, advantageously, can be used for ophthalmicapplications. The microemulsions are prepared from: a lipid phasecontaining an oily component and one or more surfactants andco-surfactants; and an aqueous phase, containing one or more surfactantsand co-surfactants. In some embodiments the aqueous phase contains onesurfactant and one co-surfactant. Additional ingredients used inemulsions and compositions for pharmaceutical use also can be included.

As described herein the microemulsions provided herein have smallparticles of relatively uniform size. As a result, the emulsions arevery stable and can be used to formulate pharmaceutically activecompounds to produce very stable compositions in which the compoundshave high bioavailability.

The microemulsions are formed by including an oil in the lipid phase,and at least one surfactant and one co-surfactant in each of the aqueousand lipid phases in precise ratios. When these ratios are used, themicroemulsions that form upon mixing the two phases, such as bytitrating the lipid phase with the aqueous phase (adding the aqueousphase into the lipid phase), have a very narrow distribution range ofvery small particles (<30 nm). As a result, the microemulsions areunusually stable, and, can be used to formulate pharmaceutically activecompounds that have limited aqueous solubility. The resultingmicroemulsion compositions, which are very stable, render thepharmaceutical compounds bioavailable.

In particular embodiments, the microemulsions are formed from aqueousand lipid phases in which:

the weight/volume ratio between the amount of surfactant andco-surfactant in the lipid phase to the amount of surfactant andco-surfactant in the aqueous phase is from 2 to 10; and theweight/volume ratio between the amount of oil component in the lipidphase to the amount of surfactant and co-surfactant in the aqueous phaseis from 0.2 to 1.0.

Additionally, in some embodiments, in the lipid phase, the weight/volumeratio between the oily component and the surfactant and co-surfactantsis from 0.05 to 1.4, inclusive.

Further details of the components of the microemulsions, including thesurfactants, oils, pharmaceutically active compounds, are describedherein.

C. Surfactants

For preparing the microemulsions each phase must include at least onesurfactant, and generally include a co-surfactant. The surfactant(s) inthe lipid and aqueous phases can be the same or different.

The surfactants and co-surfactants used for the lipid phase and for theaqueous phase have a HLB value from 8-16, in particular from 10-16, or12-14. Any biocompatible surfactant/co-surfactants suitable forpharmaceutical applications and that has an HLB in these ranges can beused in the microemulsions. There are many suchsurfactants/co-surfactants known to the those of skill in the art (seeTables and discussion below for exemplary surfactants). The skilledperson readily can select surfactants and co-surfactants for use in themicroemulsions. Selected surfactants will have an HLB within therequisite range, and will be appropriate for the intended applicationand the active agent. For example, surfactants for ophthalmic use shouldbe suitable for administration to the eye. Surfactants suitable for usein pharmaceutical compositions, include those for ophthalmicapplication. Such surfactants are well known (see, e.g., U.S. Pat. No.6,267,985).

Hydrophilic surfactants suitable for use in the microemulsioncompositions provided herein include any hydrophilic surfactants knownto those of skill in the art that have an HLB between about 8 and 16,inclusive, and generally having an HLB value greater than or equal to10. Surfactants include, but are not limited to, polyoxyethylenesorbitan fatty acid derivatives, polyoxyethylenes, hydrogenated castoroil ethoxylates, glycerol esters of fatty acids, PEGylated fatty acids,polyoxyl castor oil surfactants, poloxamers, amine oxides, and alcoholethoxylates (nonionic surfactants). Co-surfactants include glycerol andpropylene glycol. Examples include, but are not limited to,polyoxyethylene sorbitan fatty acid derivatives, such as TWEEN 20(polyethylene glycol sorbitan monolaurate; polysorbate 20; available,for example, from Sigma-Aldrich), TWEEN 80 (polyethylene glycol sorbitanmonooleate; polysorbate 80; available from Sigma-Aldrich), and MONTANOX40 (polyethylene glycol sorbitan monopalmitate; polysorbate 40).

Hydrophilic surfactants having the HLB values include castor oil orhydrogenated castor oil ethoxylates, e.g., CREMOPHOR EL (polyoxyl 35castor oil USP, available from BASF), CREMOPHOR RH40 (KOLLIPHOR RH 40;polyoxyl 40 hydrogenated castor oil USP, available from BASF), ETOCAS 40(PEG 40 castor oil, available from Croda), CRODURET 60 (PEG-60hydrogenated castor oil, available from Croda), and KOLLIPHOR HS 15(polyethylene glycol 15-hydroxystearate, available from Sigma-Aldrich).

The following table provides generic names and tradenames/trademarks ofsurfactants, by type, for pharmaceutical applications, including themicroemulsions provided herein.

Trade Name/Trademark Generic/Chemical Name HLB Class - polyoxyethylenesorbitan fatty acid derivatives TWEEN 20, Polysorbate 20 polyethyleneglycol sorbitan monolaurate 16.7 TWEEN 80, Polysorbate 80 polyethyleneglycol sorbitan monooleate 15 MONTANOX 40, Polysorbate 40, polyethyleneglycol sorbitan 15.6 Tween ® 40 monopalmitate TWEEN 60, Polysorbate 60Polyoxyethylene sorbitan monostearate 14.9 Polysorbate 61Polyoxyethylene sorbitan monostearate 9.6 Polysorbate 85 Polyoxyethylenesorbitan trioleate 11 PEG-40 Sorbitan Peroleate 9 Class -polyoxyethylenes (BRIJ) BRIJ ® L4 Polyethylene glycol dodecyl ether 9Polyoxyethylene (4) lauryl ether BRIJ ® C10 Polyethylene glycolhexadecyl ether 12 Polyoxyethylene (10) cetyl ether BRIJ ® S20Polyethylene glycol octadecyl ether 15 Polyoxyethylene (10) stearylether BRIJ ® 20 Polyoxyethylene (20) oleyl ether 15 BRIJ ® 58Polyethylene glycol hexadecyl ether 16 Polyoxyethylene (20) cetyl etherBRIJ ® L23 Polyoxyethylene (23) lauryl ether 16.9 BRIJ ® O20Polyoxyethylene (20) oleyl ether 15 Brij ® O10 (Brij ® 97)Polyoxyethylene (10) oleyl ether 12 Brij ® S10 Polyoxyethylene (10)stearyl ether 12 Brij ® C10 Polyoxyethylene (10) cetyl ether 12 Brij ®S20 Polyoxyethylene (20) stearyl ether 15 Brij ® S721 Polyoxyethylene(21) stearyl ether 16 Brij ® S 100 Polyoxyethylene (100) stearyl ether18 Brij ® CS17 Polyoxyethylene linear alkyl ether 15 Brij ® 58Polyoxyethylene (20) cetyl ether 16 Class - castor oil ethoxylates(ethylene oxide condensates of castor oil) ETOCAS 40 PEG-40 castor oil13 EMANON CO-40 Polyoxyethylene(40) castor oil 13.9 PEG-60 castor oil 16PEG-25 castor oil 11 Class - hydrogenated castor oil ethoxylates(ethylene oxide condensates of hydrogenated castor oil) CREMOPHOR RH40,KOLLIPHOR polyoxyl 40 hydrogenated castor oil 14-16 RH 40 (closer to 14)CREMOPHOR EL, KOLLIPHOR EL polyoxyl 35 castor oil 12-14 EMANON CH-25PEG-25 HYDROGENATED CASTOR OIL 10.7 Cremophor ® RH 40 PEG 40hydrogenated Castor oil 15-17 (Kolliphor ® RH40) Cremophor ® RH 60 PEG60 hydrogenated Castor oil 14-16 CRODURET 60 Class - poloxamers(nonionic tri-block copolymers containing a central hydrophobic chain ofpolyoxypropylene (poly(propylene oxide)) flanked by two hydrophilicchains of polyoxy- ethylene (poly(ethylene oxide))

Pluronic ® L-64 PEG-PPG-PEG Mn~2,900 12-18 Pluronic ® P-123 PEG-PPG-PEGMn~5,800 7-9 Pluronic ® 10R5 PEG-PPG-PEG Mn~2,000 12-18 Pluronic ® 105PEG-PPG-PEG Mn~6,500 15 PEG-PPG-PEG Mn~920 10 Class - amine oxidesAMMONYX ® LO lauryl dimethyl amine oxide 15 AMMONYX ® MO Myristamineoxide (Myristyl dimethylamine 14 oxide) AMMONYX ® DO Decylamine oxide 15AMMONYX ® LO-A Lauramine oxide 15 AMMONYX ® MMyristylamine/dimethylamine oxide 16 AROMOX DMHT Dimethyl hydrogenatedtallowalkylamine 14.4 oxide AROMOX DM16 Dimethylhexadecylamine oxide14.2 Class - polyethoxylated alcohols (contain an oleophilic,carbon-rich, fatty alcohol and a hydrophilic, polyoxyethylene chain.)ALKONAT ® CE 50 Cetearyl Alcohol Ethoxylate 5 EO 9.2 ALKONAT ® CE 200Cetearyl Alcohol Ethoxylate 20 EO 15.5 ALKONAT ® L 30 Lauryl AlcoholEthoxylate 3 EO 8.3 ALKONAT ® L 40 Lauryl Alcohol Ethoxylate 4 EO 9.7ALKONAT ® L 50 Lauryl Alcohol Ethoxylate 5 EO 10.8 ALKONAT ® L 60 LaurylAlcohol Ethoxylate 6 EO 11.7 ALKONAT ® L 120 Lauryl Alcohol Ethoxylate12 EO 14.8 ALKONAT ® E 200 Stearyl Alcohol Ethoxylate 20 EO 15.3ALKOSYNT ® ID 30 Isodecyl Alcohol Ethoxylate 3 EO 9.1 ALKOSYNT ® ID 80Isodecyl Alcohol Ethoxylate 8 EO 13.8 ALKOSYNT ® IT 50 IsotridecylAlcohol Ethoxylate 5 EO 10.7 ALKOSYNT ® IT 100 Isotridecyl AlcoholEthoxylate 10 EO 13.9 Class - alcohol ethoxylates (nonionic) BIO-SOFTN1-3 Linear alcohol (C11) ethoxylate, POE-3 8.7 BIO-SOFT N1-5 Linearalcohol (C11) ethoxylate, POE-5 11.2 BIO-SOFT N1-7 Linear alcohol (C11)ethoxylate, POE-7 12.9 BIO-SOFT N1-9 Linear alcohol (C11) ethoxylate,POE-9 13.9 BIO-SOFT N23-3 Linear alcohol (C12-13) ethoxylate, POE-3 8.1BIO-SOFT N23-6.5 Linear alcohol (C12-13) ethoxylate, POE-5 11.9 Class -glycerol esters of fatty acids KOLLIPHOR HS 15 Polyoxyl 15hydroxystearate 16 Class - PEGylated fatty acids PEG-40 SorbitanHexaoleate 10 PEG-40 Sorbitan Perisostearate 10 PEG-10 Olive Glycerides10 PEG-7 Glyceryl Cocoate 10 PEG sorbitol hexaoleate 10.2 PEG-8 Dioleate8 PEG-7 Glyceryl Cocoate 11 Cetearyl Glucoside 11 PEG-8 Stearate 11.1PEG sorbitan tetraoleate 11.4 PEG-15 Glyceryl Isostearate 11.4 PEG-400monooleate 11.4 PEG-400 monostearate 11.6 PEG-8 Oleate 11.6 Class -alcohol ethoxylates (nonionic) BIO-SOFT N1-3 Linear alcohol (C11)ethoxylate, POE-3 8.7 BIO-SOFT N1-5 Linear alcohol (C11) ethoxylate,POE-5 11.2 BIO-SOFT N1-7 Linear alcohol (C11) ethoxylate, POE-7 12.9BIO-SOFT N1-9 Linear alcohol (C11) ethoxylate, POE-9 13.9 BIO-SOFT N23-3Linear alcohol (C12-13) ethoxylate, POE-3 8.1 BIO-SOFT N23-6.5 Linearalcohol (C12-13) ethoxylate, POE-5 11.9

Table Exemplary Surfactants and Co-Surfactants for use in themicroemulsions Surfactant/co-surfactant HLB PEG-8 Dioleate 8 SorbitanLaurate 8.6 Polyethylene glycol dodecyl ether Polyoxyethylene 9 (4)lauryl ether (BRIJ ® L4) PEG-40 Sorbitan Peroleate 9 Polyoxyethylenesorbitan monostearate (Tween 61) 9.6 Laureth-4 9.7 Polysorbate 80 10Polyethylene-block-poly(ethylene glycol) average 10 Mn ~1,400Polyoxyethylene (5) nonylphenylether, branched 10 (IGEPAL ® CO-520)Poly(ethylene glycol) sorbitol hexaoleate 10 PEG-40 Sorbitan Hexaoleate10 PEG-40 Sorbitan Perisostearate 10 PEG-10 Olive Glycerides 10 PEG-7Glyceryl Cocoate 10 PEG sorbitol hexaoleate 10.2 Polyoxyethylenesorbitan tristearate (Tween 65) 10.5 PEG-25 Hydrogenated Castor Oil 10.8Polyoxyethylene sorbitan trioleate (Polysorbate 85) 11 PEG-7 GlycerylCocoate 11 Cetearyl Glucoside 11 PEG-8 Stearate 11.1 PEG sorbitantetraoleate 11.4 PEG-15 Glyceryl Isostearate 11.4 PEG-400 monooleate11.4 PEG-400 monostearate 11.6 PEG-8 Oleate 11.6 Poly(propyleneglycol)-block-poly(ethylene glycol)-block-  7-12 poly(propylene glycol)average Mn ~2,700 (PPG-PEG- PPG Pluronic ® 17R4) CaprylocaproylPolyoxyl-8 glycerides (Labrasol ®) 12 PEG-15 Glyceryl Isostearate 12PEG-35 Almond Glycerides 12 Polyglyceryl-3 Methylglucose distearate 12Polyethylene glycol hexadecyl ether Polyoxyethylene (10) 12 cetyl ether(BRIJ ® C10) Oleth-10 12.4 Ceth-10 12.9 Polyoxyethylene (9)nonylphenylether, branched 13 (IGEPAL ® CO-630) PEG-8 Laurate 13 PEG-400monolaurate 13.1 Polyoxyethylene sorbitan monolaurate (Tween 21) 13.3Polyoxyethylene (12) isooctylphenyl ether Polyoxyethylene 14 (12)octylphenyl ether, branched (IGEPAL ® CA-720) Polyoxyethylene (12)tridecyl ether 14 PEG-8 glyceryl caprylate/caprate 14 PEG-32 glyceryllaurate 14 Polyethylene glycol sorbitan monostearate Polyoxyethylene14.9 sorbitan monostearate (TWEEN ® 60) Polyethylene glycol octadecylether Polyoxyethylene 15 (10) stearyl ether (BRIJ ® S20) Polyoxyethylenesorbitan monooleate (Polysorbate 80) 15 Polyoxyethylene (18) tridecylether 15 PEG-60 Almond glycerides 15 Polyoxyethylene (20) oleyl ether(BRIJ ® 20) 15 PEG-20 glyceryl stearate 15 PEG-20 stearyl ether 15.3PEG-20 oleyl ether 15.3 Polyoxyethylenesorbitan monopalmitate (TWEEN ®40) 15.6 PEG-20 hexadecyl ether 15.7 Polyethylene glycol hexadecyl etherPolyoxyethylene 16 (20) cetyl ether (BRIJ ® 58) Polyoxyl 35 castor oil(Macrogolglycerol ricinoleate) 12-14 (Cremophor EL) Polyoxyl 40 castoroil (Cremophor RH 40) 14-16 Polyoxyl hydrogenated castor oil (CremophorRH 60) 15-17 PEG-PPG-PEG Pluronic ® L-64 12-18 Poly(propyleneglycol)-block-poly(ethylene glycol)- 12-18 block-poly(propylene glycol)average M_(n) ~2,000 (PPG-PEG-PPG Pluronic ® 10R5)

The surfactants and HLB values set forth in the Tables above areexemplary. Any known surfactant or co-surfactant, suitable for use in apharmaceutical composition, can be used in the emulsions providedherein.

1. Exemplary Surfactants/Co-Surfactants in the Lipid Phase

For example, in the lipid phase, exemplary surfactants are of thenonionic type such as, but not limited to, for example: poloxamers, suchas those sold under the trademarks Pluronic®, a hydrogenated castor oilethoxylate, such as Kolliphor® and Cremophor®, polysorbates (such asTween™), lauryl dimethyl amine oxide, polyethoxylated alcohol, polyoxyllauryl ether, nonionic polyoxyethylene surfactants, such as that soldunder the trademark Brij®, polyoxyl castor oil, lecithin, poloxamers,polyethylene glycol, and glycerol esters of fatty acids. In someembodiments, the co-surfactant in the lipid phase is/are propyleneglycol and/or glycerol.

2. Exemplary Surfactants/Co-Surfactants in the Aqueous Phase

In the aqueous phase, exemplary surfactants are of the nonionic typesuch as, but not limited to, for example: poloxamers, such as those soldunder the trademark Pluronic®, hydrogenated castor oil ethoxylates, suchas Cremophor®, and Kolliphor®, polysorbates, such, as Tween™, Lauryldimethyl amine oxide, polyethoxylated alcohol, polyoxyl lauryl ether,nonionic polyoxyethylene surfactants, such as those sold under thetrademark Brij®, polyoxyl castor oil, lecithin, polyethylene glycol,glycerol esters of fatty acids. In some embodiments, theco-surfactant(s) in the aqueous phase is propylene glycol and/orglycerol.

D. Aqueous Phase Components

The aqueous phase includes polar protic solvents, generally thosesuitable for ophthalmic applications, such as water. The aqueous phaseincludes all polar and water-soluble ingredients, and include asurfactant and a co-surfactant. Other ingredients in the aqueous phasecan include alcohols and glycerin and other such solvents.

E. Lipid Phase Components

The lipid phase includes at least one oil, and non-polar ingredients,including pharmaceutical agents/drugs that are not soluble in aqueouscompositions. The lipid phase includes at least one oil. The oil can bea natural oil or synthetic oil, and must be one that is biocompatible.Suitable natural oils, include, but are not limited to, vegetable and/oranimal oils, such as, by way of example soya oil, corn oil, linseed oil,sunflower oil, krill oil, cod-liver oil, fish oil, avocado oil, almondoil, babassu oil, borage oil, carob oil, cashew nut oil, grapeseed oil,coconut oil, Oryza sativa bran oil, castor oil, hemp seed oil, jojobaoil, peanut oil, poppy seed oil, sesame oil, walnut oil, olive oil,wheat-germ oil, argan oil, cottonseed oil, blackcurrant seed oil, andoils rich in PUFAs by a fraction greater than 10%. Mineral oils ofsynthetic origin, such as, by way of example esters of medium andlong-chain fatty acids, medium and long-chain triglycerides.

F. Additional Ingredients

The microemulsions can include additional ingredients suitable anduseful in pharmaceutical compositions. The following are exemplary ofsuch ingredients. All should be biocompatible so that they can be, forexample, topically applied to the eye or injected into the eye oringested or administered parentally.

1. Buffers

The microemulsions can include buffers to maintain the pH at a desiredrange, generally between about 5.0 and 8, such as between 5.2 and 8,such as 7.4 or 7.5. Exemplary biocompatible suitable buffers include,but are not limited to: Trometamol (Tris buffer,2-Amino-2-(hydroxymethyl) propane-1, 3-diol), Mcllvaine(citrate-phosphate buffer), Sorensen (0.133 M Na₂HP040.133 M KH₂PO₄ pH7.2), sodium lactate, sodium acetate, sodium borate, boric acid, andimidazole. An exemplary buffer is histidine and citrate adjusted to pHwith NaOH or HCl. The suitable buffer concentration is in the range of10-50 mM.

2. Tonicity Agents

The microemulsions can include isotonizing agents. These compounds areused to achieve the required tonicity in the preparation. Exemplary ofthese are glycerol, sorbitol, mannitol, sucrose, trehalose, propyleneglycol, dextrose, ethylene glycol, sodium chloride, potassium chloride,magnesium chloride, and calcium chloride. In one embodiment, themicroemulsion comprises excipients such as: stabilizing agents,antioxidants, antimicrobials, thickening agents, branched and linearpolymers. Tonicity agents are used at concentrations that guaranteeosmolality of the formulation ranging, for example, between 100-400,inclusive, mOsmol/kg of the composition

3. Stabilizing Agents

The stabilizing agents are chosen by way of example from glycine,proline, cyclodextrins, calixarenes, hypromellose, histidine, betaine,albumin, L-carnitine, taurine, glyceryl monostearate, pectins, polyvinylalcohol, and propylene glycol. It is within the skill in the art todetermine an appropriate concentration, which depends upon, for example,the particular stabilizing agent(s) and the other components of thecomposition. For example, the amount can be between 0.0001% to 20% w/v,inclusive.

4. Thickening Agents

The microemulsions can include thickening agents. The thickening agentsinclude, but are not limited to, those extracted from plants, microbesand animals. Many thickening agents are known to those of skill in theart. Exemplary of thickening agents extracted from plants are gums.Exemplary of thickening agents are gums, such as gums extracted fromplants belonging to the genera Cyamopsis, Sterculia, Ipomoea,Trigonella, Cassia, Physaria, Tamarindus, Ceratonia, Caesalpinia;exudates of vegetable origin, such as, by way of example those relatedto species belonging to the genera Manilkara, Amorphophallus, Acacia,Anogeissus, Sterculia, Astragalus; gums of microbic origin, such as, byway of example dextran, gellan gum, xanthan gum; extracts of marineorigin, such as, by way of example sodium alginate, alginic acid,carrageenan, agar-agar, and derivatives of Ulva lactuca, Alga nori,Arthrospira platensis; derivatives of animal origin, such as, by way ofexample chitin and chitosan, hyaluronic acid; derivatives of cellulose,such as, by way of example carboxymethylcellulose (CMC), hydroxyethylcellulose, hydroxypropyl methyl cellulose (HPMC), methylcellulose (MC),microcrystalline cellulose (MCC).

5. Antioxidants

Antioxidants can be included in the microemulsion compositions.Exemplary of antioxidants are α-tocopherol, flavonoids (e.g.resveratrol, epigallocatechin-3-gallate, quercetin, naringenin,delphinidin) coenzyme Q10, NDGA (nordihydroguaiaretic acid), meso-NDGA,sodium ascorbate, L-ascorbic acid, N-acetylcarnosine, citric acid,erythorbic acid, L-6-ascorbyl palmitate, L-carnosine, L-glutathione,L-cysteine, cysteine ascorbate. The amount can be determined by theskilled person. It can depend upon the particular antioxidant(s)employed and the other components of the composition. An exemplary rangeis between 0.0001% and 5.0% w/v, inclusive.

G. Microemulsion Compositions Containing Active Ingredients

The microemulsion compositions provided herein are to be used aspharmaceutically acceptable carriers for formulating biologically activemolecules, such as small molecule drugs and biologics. Themicroemulsions provided herein are advantageous for formulating activeagents that have low solubility in aqueous solutions. The microemulsionsprovided are used to formulate such active agents in a form that isstable and can also be preserved at room temperature.

The microemulsions provided herein can be used for oral, parenteral,topical and local application. In particular embodiments, the emulsionsare for ophthalmic administration. The microemulsions can be formulated,for example, for topical application, such as eye drops, or forinjection, such as intravitreal injection, depending upon theindication.

1. Active Ingredients

Active ingredients include pharmaceutically and biologically activecompounds, such as small molecule drugs and biologics, particularlyagents that have limited solubility in aqueous compositions. The activeagents are formulated, generally by adding them to the lipid phase, andthen, mixing the lipid phase with the aqueous phase, such as bytitration as described herein. The lipid and aqueous phases contain therequired amounts and ratios of surfactants/co-surfactants and lipids asdescribed herein. The microemulsions that form are characterized byhaving small particles (<30 nm, such as 15 nm±10 nm), and a narrowparticle size range distribution, such as a PDI<0.2, high thermodynamicstability, and good bioavailability and activity of the formulatedactive agent.

The microemulsions generally contain less than 5% (w/v) of the activeagent, but can contain any amount of interest, such as 0.01 mg/ml to 50mg/ml, such as 0.01 to 30 mg/ml. The particular amount(s) depends uponthe pharmaceutical, the indication for which it is used, the route ofadministration, and the subject. It is well within the skill in the artto formulate the agent at an appropriate concentration.

Active ingredients include any known pharmaceutical, particularly thosewith low solubility in aqueous compositions. Included, for example areany pharmaceutical molecules chosen from the groups as defined by theUnited States Pharmacopeia (USP). These include, but are not limited to,gastrointestinal agents, antispasmodics, blood sugar regulators,nutraceuticals/minerals/electrolytes, platelet modifying agents,coagulants, cardiovascular agents, alpha-adrenergicagonists/alpha-adrenergic antagonists/vasodilators/arterialvasodilators, carbonic anhydrase inhibitor diuretics/loopdiuretics/potassium-sparing diuretics/thiazide diuretics, othercardiovascular agents, beta-adrenergic antagonists, calcium channelblockers, angiotensin converting enzyme inhibitors (ACE),dyslipidemics/HMG CoA Reductase inhibitors (Statins), anti-fungals,dermatological agents, anti-histamines, anesthetics, anti-bacterials,hormone-stimulating agents/substituents/modifiers (adrenals, pituitaryand sex hormones), glycemic agents, hormone-suppressing agents(parathyroids), anti-mycobacterials, anti-virals, anti-neoplastics,immunomodulators, anti-inflammatory agents, analgesics,anti-convulsants, anti-Parkinson agents, anti-psychotics,anti-depressants/anti-dementia agents/anti-anxiety medication,anti-myasthenic agents/agents for treating substances of abuse/centralnervous system agents,bronchodilators/sympathomimetics/anti-cholinergics/inhaledcorticosteroids/phosphodiesterase inhibitors/airborne disorders, otheragents of the respiratory tract, anti-parasites, anti-glaucomaophthalmic agents, other ophthalmic agents/anti-allergic ophthalmicagents, ophthalmic anti-inflammatories, prostaglandin analogues andophthalmic prostamides.

Active ingredients also include, but are not limited to, any from thegroups defined by the Anatomical Therapeutic Chemical ClassificationSystem (ATC) compiled by the World Health Organization. These includedrugs for acidity-related disorders (A02), drugs for gastrointestinalfunction disorders (A03), drugs used for diabetes (A10), vitamins (A11),mineral supplements (A12), antithrombotic agents (B01),anti-hemorrhagics (B02), cardiac therapy drugs (C01), anti-hypertensives(C02), diuretics (C03), peripheral vasodilators (C04), vasoprotectives(C05), beta-blocking agents (C07), calcium-antagonists (C08), drugsacting on the renin-angiotensin system (C09), lipid-lowering drugs(C10), anti-fungals for dermatological use (D01), emollients andprotectives (D02), drugs for injuries and ulcers (D03), antipruritics,including anti-histamines, anaesthetics (D04), anti-psoriasis drugs(D05), antibiotics and chemotherapeutic agents for dermatological use(D06), antiseptics and disinfectants (D08), hyphophyseal, hypothalamichormones and similar (H01), systemic corticosteroids (H02), thyroidtherapy (H03), pancreatic hormones (H04), homeostatic calcium (H05),anti-bacterials for systemic use (J01), anti-mycotics for systemic use(J02), anti-mycobacterials (J04), anti-viral drugs for systemic use(J05), immune serums and immunoglobulins (J06), anti-neoplastic agents(L01), endocrine therapy (L02), immunostimulants (L03),immunosuppressants (L04), anti-inflammatories and anti-rheumatics (M01),topical products for joint and muscle pain (M02), anesthetics (N01),analgesics (N02), anti-epileptics (N03), anti-parkinsonians (N04),psycholeptics (N05), psychoanaleptics (N06), other nervous system drugs(N07), rhinologic preparations (R01), preparations for the pharyngealcavity (R02), drugs for obstructive disorders of the respiratory tract(R03), preparations for coughs and colds (R05), anti-histamines forsystemic use (R06), other preparations for the respiratory system (R07),anti-infectives (S01A), anti-inflammatory agents (S01B),anti-inflammatory agents and anti-infectives combined (S01C),anti-glaucoma agents and miotics (S01E), mydriatics and cyclopegics(S01F), decongestants and anti-allergens (S01G), local anaesthetics(S01H), diagnostic agents (S01J), surgical aids (S01K), ocular vascularagents (S01L), anti-infectives (S03A), corticosteroids (S03B), andcorticosteroids combined with anti-infectives (S03C).

2. Ophthalmic Agents

The microemulsions as described herein are particularly suitable forophthalmic applications. Thus, any ophthalmic drug can be formulated inthe microemulsions. Drugs for ocular use include, but are not limitedto, steroidal anti-inflammatory agents, antimicrobial drugs,anti-glaucoma agents, antihypertensives, diagnostic agents, antiviralagents, anti-angiogenic agents, neuroprotectants, and antioxidants.These ingredients can be used alone or in combination.

For example, the active ingredient can be for treatment of ocularhypertension or glaucoma such as, for example: prostaglandins(latanoprost, travoprost, bimatoprost), beta-blockers (timolol,carteolol, levobunolol, betaxolol, nebivolol), parasympathomimetics(pilocarpine), alpha2-agonists (apraclonidine, brimonidine), carbonicanhydrase inhibitors CAI-(brinzolamide, dorzolamide), and derivativesthereof. In one exemplary embodiment, the active ingredient in themicroemulsion is chosen from one or more prostaglandin analogs, such as,for example latanoprost, travoprost, bimatoprost, and derivatives.

In other embodiments, the active ingredient is an anti-angiogenic, suchas, for example sorafenib, sorafenib tosylate, regorafenib, regorafenibtosylate, regorafenib isethionate, regorafenib ethylsulfonate,apremilast, radotinib, spironolactone, or an anti-oxidant, such asnordihydroguaiaretic acid, meso-nordihydroguaiaretic acid (masoprocol),a hydrate, solvate, metabolite or a salt from these, which is acceptablefrom a pharmaceutical point of view, or a polymorphic crystalline formof the molecules; or the molecule can be a beta-blocker, such astimolol, betaxolol, levobunolol, nebivolol and carteolol; or it is acorticosteroid, such as dexamethasone, or a non-steroidalanti-inflammatory drug (NSAID) or a mixture of two or more of the activeingredients.

The microemulsions contain active ingredients in a concentration rangefrom about 0.01 to 50 mg/ml, such as 0.01 to 30 mg/ml. The results shownand described herein demonstrate that the microemulsion confer enhancedstability to the active ingredients, without interfering with thebiological action of the active ingredient. For example, Example 6 showsthat microemulsions provided herein effectively carry various activeingredients, alone and in combination. The microemulsions conferstability to the active ingredient included in the formulation. Forexample, Example 11, shows latanoprost activity in the resultingmicroemulsion, measured in vivo, is at least comparable to that observedusing latanoprost in a commercial ophthalmic solution. The chemicalstability of the active ingredient is maintained at room temperature.

For example, microemulsions containing masoprocol or sorafenib tosylateare effective in animal models of retinal ischemia-reperfusion,choroidal neovascularization and diabetic retinopathy. As shown inExample 16, microemulsions containing masoprocol 0.302% (formulation 04)are effective in a murine model of dry eye, a pathology of the surfaceof the eye.

Thus, microemulsions as provided herein permit formulation of any knownpharmaceutically active agent, and provide enhanced stability, whileretaining activity at least comparable to other formulations that do notconfer the enhanced stability.

H. Diseases and Conditions of the Eye and Methods of Treatment

The microemulsions provided herein can serve as vehicle foradministration of any active agent, particularly those of low solubilityin aqueous compositions. The microemulsions can be used for treatment ofophthalmic disorders by formulating active agents used for treatingdisorders, conditions and diseases of the eye. The microemulsionsprovided herein are particularly suitable for these indications becausethey contain ingredients that are compatible with the tissues of theeye, and because they can provide these agents in a form that is stableand has good bioavailability. These conditions, diseases and disorders,include ophthalmic conditions and pathologies, such as, but not limitedto glaucoma, Age-Related Macular Degeneration AMD, diabetic retinopathy,neuropathies, bacterial infections, viral infections, dry eye, allergicand/or inflammation in the eye. The microemulsions can be formulated fortopical administration to the eye or for injection or any suitableroute.

Different types of diseases affect the eye. The eye is divided into twosegments: (1) the anterior segment that contains the cornea, iris,pupil, conjunctiva, ciliary body, anterior chamber, aqueous humor,trabecular meshwork, and lens; and (2) the posterior segment thatcontains the vitreous humor, sclera, choroid, retina, macula and opticnerve. There are many diseases and conditions of the eye, andpharmaceutically active agents that are used to treat such diseases andconditions. Administration can be effected by any route, such astopically using eye drops, and by injections, such as intravitrealinjection. Treatment is important as some diseases eventually lead toblindness.

The following are exemplary of diseases that can be treated, and drugsthat can be formulated in the microemulsions provided herein.

1. Glaucoma

Glaucoma is a multifaceted disorder resulting from damage to the retinalganglion cells and their axons, causing progressive optic nervedegeneration and leading to irreversible blindness in some patients.There are two main categories of glaucoma that are characterized by anelevated intraocular pressure (IOP) such as Open-angle glaucoma (OAG)and Angle-closure glaucoma (ACG). OAG is a chronic condition where thereis a partial blockage within the trabecular meshwork or Schlemm's canalthat compromises the ability of the aqueous humor (AqH) to be properlydrained from the eye, resulting in an increased IOP. ACG is defined by aclosing of the iridocorneal angle within the anterior chamber, and iscaused by factors that either pull or push the iris up into the anteriorchamber. This change in morphology can physically block the drainage ofAqH by restricting flow through the iridocorneal canal and trabecularmeshwork. Moreover, there is a Normal-tension glaucoma (NTG) that is aform of OAG characterized by glaucomatous optic neuropathy in patientswith IOP measurements consistently lower than 21 mmHg.

Drugs for treatment of glaucoma include prostaglandin analogs, such as,latanoprost, bimatoprost, travoprost and tafluprost; beta-blockers, suchas timolol, carteolol, levobunolol and betaxolol, and alpha-adrenergicagonists, such as brimonidine and apraclonidine, and carbonic anhydraseinhibitors, such as dorzolamide and brinzolamide, and pharmaceuticallyacceptable derivatives, hydrates, solvates, metabolites and saltsthereof, or a polymorphic crystalline form of the molecules. Moreover,since 2014, new classes of drugs have been developed with new mechanismsof action, such as nitric oxide (NO)-donating prostaglandin F2-alphaanalogue (latanoprostene bunod), rho kinase inhibitors (ripasudil andnetarsudil mesylate) and prostaglandin EP2 receptor agonist (DE-117).

2. Macular Degeneration

Age-related macular degeneration (AMD) is a disease that affects themacular region of the retina, causing progressive loss of centralvision; it is a multifactorial disorder, with dysregulation in thecomplement, lipid, angiogenic, inflammatory, and extracellular matrixpathways implicated in its pathogenesis. By 2020, the number of peoplewith AMD globally is expected to be around 200 million, increasing tonearly 300 million by 2040. There are two major forms of MD, withdifferent prognosis and therapy: the atrophic or dry-type MD,representing approximately the 85-90% of the total number of cases, andthe neovascular or wet-type MD. The initial alteration of the fundus isoften represented by the so-called drusen, or colloids bodies, that aredegenerative formations of yellowish color and round shape mostly foundat the posterior pole. Considering the mechanisms inducing the chronicretinal damage, an alteration of the metabolic sustainment of thephotoreceptors cells (rods and cones) and of the retinal pigmentepithelium (RPE) is supposed, depending on inflammation processes andvascular modifications. Among the drugs for Wet AMD are VEGFantagonists, and, also inhibitors of complement activation that targetcomplement C3 or C5. Exemplary of such drugs, which are administered byintravitreal injection, are ranibizumab (trade name: Lucentis), andaflibercept (Eylea), pegaptanib (Macugen®), and bevacizumab (Avastin®).Classes of drugs with other mechanisms of action are being developed.These include, for example, anti-complement agent (C3 Inhibitor)(APL-2), anti-complement agent avacincaptad pegol (C5 Inhibitor;Zimura®), alpha2-adrenergic receptor agonist (Brimo DDS), DARPin basedanti-VEGF (abicipar pegol), scFv anti-VEGF antibody fragment(brolucizumab), anti-VEGF-C and VEGF-D (OPT-302). There are alsopromising drugs in early-stage development such as targets C5/complementfactor F (CLG561/LFG316 combination), binds Ang2/VEGF as a singlemolecule (RG7716), anti-endoglin antibody (DE-122), VEGF inhibitor(LHA510 and PAN-90806), integrin av133 antagonist (SF0166), PDGF/VEGFinhibitor (X-82), CTGF inhibitor (RXI-109), VEGF, PDGF and bFGFinhibitor (squalamine lactate), PPAR-alpha agonist (BIO-201),antioxidant/NF-kB inhibitor (CPC-551), mPTP opening blocker (ocuvia),16S rRNA of 30s ribosomal subunit inhibitor (FMX-103), tissue factorinhibitor (ICON-1), MASP-2 antibody (OMS-721), β-amyloid inhibitor(ALZ-801) and ROBO4 agonist (DS-7080).

3. Dry Eye

Dry eye is a multifactorial disease of the ocular surface characterizedby a loss of homeostasis of the tear film, and accompanied by ocularsymptoms, in which tear film instability and hyperosmolarity, ocularsurface inflammation and damage, and neurosensory abnormalities playetiological roles. The management of this ocular disease is dominated bythe widespread use of artificial tears that contain hydrogel polymerssuch as sodium hyaluronate and methylcellulose; corticosteroids such asfluorometholone, prednisolone and dexamethasone; immunosuppressant andanti-inflammatory such as, cyclosporine. Moreover, new classes of drugshave been developed with new mechanisms of action, such as P2Y2 receptoragonist (diquafosol tetrasodium); mucin secretagogue (rebamipide);integrin inhibitor and anti-inflammatory (lifitegrast); TrkA agonist andneurotrophin peptidomimetic (tavilermide); mitochondrial antioxidant(visomitin) and recombinant human nerve growth factor (RH-NGF). Otherdrugs in clinical development. These, include, for example, as thymosinbeta 4/synthetic peptide (RGN-259), RNAi-based TRPV1 inhibitor(tivanisiran), aldehydetrap (reproxalap) and recombinant humanlubricinprotein (ECF-843) and promising drugs in early-stage developmentsuch as a synthetic fragment of lacritin (lacripep), calcineurininhibitor (voclosporin), epithelial sodium channel blocker (P-321).

4. Meibomian Gland Dysfunction (MGD)

Meibomian gland dysfunction (MGD) is a chronic, diffuse abnormality ofthe meibomian glands, commonly characterized by terminal ductobstruction and/or qualitative/quantitative changes in the glandularsecretion. This may result in alteration of the tear film, symptoms ofeye irritation, clinically apparent inflammation, and ocular surfacedisease. MGD can lead to alterations in the normal lipid composition inmeibomian gland secretions. Lipid abnormalities can lead toabnormalities of tear film composition and function resulting inevaporative dry eye. Systemic minocycline and doxycycline are known toproduce significant effects in the management of MGD.

5. Cataract

Cataract is the opacification of the eye lens resulting in a change tothe refractive index and therefore creating a loss of vision. Dependingon the location of the opacification, an age-related cataract can beclassified as cortical, nuclear, or posterior subcapsular cataract. Inaddition to aging, eye injuries, infections, and surgeries can causecataract formation. Even though surgical therapy is well established andeffective, it cannot be performed in many developing countries due tothe lack of both the required instrumentation and medical professionals.The development of nonsurgical treatments is crucial for preventing andreversing cataracts. Interestingly, antioxidants, chaperones, chaperoneactivators, and protein aggregation inhibitors are promising drugcandidates. For example, eye drops containing lanosterol have been shownto improve vision.

6. Diabetic Retinopathy and Macular Edema

Diabetic retinopathy (DR) and macular edema, the most-fearedcomplication of diabetes mellitus, is the most frequent cause of newcases of blindness (28.5%) among adults aged 20-74 years. DR isclinically classified into nonproliferative and proliferative diseasestages. In nonproliferative DR (NPDR), intraretinal microvascularchanges occur including microaneurysms, altered retinal vascularpermeability and eventual retinal vessel closure and nonperfusion. PDRinvolves the formation of new blood vessels on the retina or the opticdisk. These new abnormal blood vessels erupt through the surface of theretina and proliferate into the vitreous cavity of the eye, where theycan hemorrhage into the vitreous, resulting in visual loss. Treatmentsinclude anti-inflammatories, and VEGF-inhibitors

7. Infections and Allergies

Infections of the eye are treated with appropriate antibiotics,anti-virals, anti-fungals, anti-inflammatories and combinations thereofand combinations with antibiotics. The particular treatment depends typeof infection and locus of the infection.

I. Methods of Making the Microemulsion

The microemulsions can be prepared by preparing the aqueous phase andlipophilic phase containing surfactants/co-surfactants in amounts withinor at the ratios described herein, and then mixing the phases, whichform the microemulsions. Exemplary of the methods for preparingmicroemulsions herein are those depicted in FIG. 1 and FIG. 2. Anexemplary method, includes the steps of:

preparing the lipid phase, where a mixture of one or moresurfactants/co-surfactants is solubilized in oil, mixing from 1 to 10parts of the mixture for every part of oil;

-   -   preparing the aqueous phase, where a surfactant/co-surfactant        mixture plus any excipients is solubilized in water or other        polar protic solvent;    -   titrating of the lipid phase with the aqueous phase to produce a        microemulsion where 0.4-4.0% (w/v) of the microemulsion is        composed of the oily component of the lipid phase, 4.0%-36.0%        (w/v) of the microemulsion is composed of the        surfactants/co-surfactants of the lipid phase, and 1.66%-4.15%        (w/v) of the total surfactants/co-surfactants are the        surfactants/co-surfactants from the aqueous phase.

In one embodiment, the lipid and aqueous phases are combined by slowmagnetic-driven mixing. The titration can be performed at a speed, whichis described by the following equation:

V _(tit) =k×(v _(tot)/1000 ml),

where V_(tit)=titration speed in ml×min⁻¹, k=2 ml×min⁻¹, V_(tot)=totalvolume of the formulation in ml.

The micellar dimension in the resulting composition is about 15±10 nmand the polydispersity index (PDI) is within the range 0.02-0.380, or0.02 to 0.2, or 0.02 to 0.15, inclusive, or is less than 0.2 or lessthan 0.12 or less than 0.1. The preparation is performed at roomtemperature.

Advantageously, the microemulsions provided herein, particularly thosethat are intended for ophthalmic indications, do not contain anyco-surfactant of an alcoholic nature. The resulting microemulsions,thus, are biocompatible, i.e. well tolerated, with ocular tissues.

J. Examples

The following examples are included for illustrative purposes only andare not intended to limit the scope of the invention.

Example 1 Illustrative Microemulsions

A series of microemulsions that contain amounts of surfactants andco-surfactants and lipid phase in accord with the ratios and amounts asprovided herein were prepared. One formulation, designated formulation5, was prepared with amounts outside the ratios, to demonstrate theeffect of the ratios. Formulations with active drugs also were preparedto assess various parameters and activities. The ratios to formmicroemulsions with the advantageous properties described herein are,for example:

weight/volume ratio between surfactant/co-surfactant in the lipid phaseand surfactant/co-surfactant in the aqueous phase is from 2 to 10, suchas 2.2 to 9.8 or 2.4 to 8.6, and

the weight/volume ratio between the oily component of the lipid phaseand the surfactants/co-surfactants in the aqueous phase is from 0.2 to1.0, such as from 0.22 to 0.98, or 0.24 to 0.96.

In the lipid phase of microemulsions, the weight/volume ratio betweenthe oily component of the lipid phase, and the mixture of thesurfactants/co-surfactants is from 0.05 to 1.4, such as from 0.07 to1.2, or 0.1 to 1.

Five formulations were obtained using isopropyl myristate as an oilyphase, water as a dispersant, Tween 80 and Kolliphor RH40 as emulsifyingagents (surfactants), propylene glycol (co-surfactants) as a wettingagent, sodium citrate dihydrate as a buffer, and citric acid as a pHadjuster. As detailed below, the emulsifiers and the wetting agent arethe surfactant and co-surfactants, respectively, in the lipid phaseand/or in the aqueous phase, respectively.

Microemulsion for Ophthalmic Use, Formulation 1:

Components % w/v Isopropyl myristate 0.400 Tween 80 2.700 Kolliphor RH401.245 Propylene glycol 1.765 Sodium citrate dihydrate 0.500 Citric acid0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Tween 80 and propylene glycol are the surfactant/co-surfactant in thelipid phase. The Tween 80 and the propylene glycol are in a ratio of2:1. In the aqueous phase, the surfactant and co-surfactant areKolliphor RH40 and propylene glycol, respectively. In the aqueous phase,the Kolliphor RH40 and the propylene glycol are in a ratio of 3:1. Informulation 1, the surfactant/co-surfactant in the lipid phase are 4.05%(w/v) of the microemulsion and the surfactant/co-surfactant of theaqueous phase are 1.66% (w/v) of the microemulsion.

Microemulsion for Ophthalmic Use, Formulation 2:

Components % w/v Isopropyl myristate 1.410 Tween 80 4.150 Kolliphor RH4011.410 Propylene glycol 7.260 Sodium citrate dihydrate 0.500 Citric acid0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Tween 80, Propylene glycol and Kolliphor RH40 are thesurfactants/co-surfactants of the lipid phase. In the lipid phase, theTween 80, the propylene glycol and the Kolliphor RH40 are in a ratio of1:2:1.5. Kolliphor RH40 and propylene glycol are thesurfactants/co-surfactants in the aqueous phase, where, in the aqueousphase, the Kolliphor RH40 and the propylene glycol are in a ratio of3:1. In formulation 2, the surfactants/co-surfactants of the lipid phaseare 18.67% (w/v) of the microemulsion and the surfactants/co-surfactantsof the aqueous phase are 4.15% (w/v) of the microemulsion.

Microemulsion for Ophthalmic Use, Formulation 3:

Components % w/v Isopropyl myristate 4.000 Tween 80 8.000 Kolliphor RH4019.110 Propylene glycol 13.040 Sodium citrate dihydrate 0.500 Citricacid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Tween 80, Propylene glycol and Kolliphor RH40 are thesurfactants/co-surfactants of the lipid phase, where, in the lipidphase, the Tween 80, the propylene glycol and the Kolliphor RH40 are ina ratio of 1:2:1.5; Kolliphor RH40 and propylene glycol are thesurfactants/co-surfactants of the aqueous phase, where, in the aqueousphase, the Kolliphor RH40 and the propylene glycol are in a ratio of3:1. In formulation 3, the surfactants/co-surfactants of the lipid phaseare 36% (w/v) of the microemulsion and the surfactants/co-surfactants ofthe aqueous phase are 4.15% (w/v) of the microemulsion.

Microemulsion for Ophthalmic Use, Formulation 4:

Components % w/v Isopropyl myristate 0.400 Tween 80 0.900 Kolliphor RH403.045 Propylene glycol 1.765 Sodium citrate dihydrate 0.500 Citric acid0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Tween 80, Propylene glycol and Kolliphor RH40 are thesurfactants/co-surfactants of the lipid phase, where, in the lipidphase, the Tween 80, the propylene glycol and the Kolliphor RH40 are ina ratio of 1:2:1.5; Kolliphor RH40 and propylene glycol are thesurfactants/co-surfactants of the aqueous phase, where, in the aqueousphase, the Kolliphor RH40 and the propylene glycol are in a ratio of3:1. In formulation 4, the surfactants/co-surfactants of the lipid phaseare 4.05% (w/v) of the microemulsion and the surfactants/co-surfactantsof the aqueous phase are 1.66% (w/v) of the microemulsion.

Formulation 5—Comparison Formulation

Components % w/v Isopropyl myristate 0.500 Tween 80 3.390 Kolliphor RH401.965 Propylene glycol 2.350 Sodium citrate dihydrate 0.500 Citric acid0.1N q.s. pH 7.40 Purified water q.s. 100 ml

The ingredients in formulation 5, described below, do not meet therequisite ratios. It is specifically composed so that the ratio betweenthe oily component and surfactants/co-surfactants in the aqueous phase,and the ratio between surfactants/co-surfactants in the lipid phase andsurfactants/co-surfactants in the aqueous phase do not fall within theparameters of the emulsions as provided herein. It was prepared forcomparison with the microemulsions provided herein to demonstrate thatthe advantageous properties of the microemulsions provided herein derivefrom the ratios.

Tween 80 and propylene glycol are the surfactants/co-surfactants in thelipid phase, where, in the lipid phase, the Tween 80 and the propyleneglycol are in a ratio of 2:1; Kolliphor RH40 and propylene glycol arethe surfactants/co-surfactants of the aqueous phase, where, in theaqueous phase, the Kolliphor RH40 and the propylene glycol are in aratio of 3:1. In formulation 5, the surfactants/co-surfactants of thelipid phase are 5.08% (w/v) of the microemulsion and thesurfactants/co-surfactants of the aqueous phase are 2.62% (w/v) ofmicroemulsion.

Formulations 6-9

Four formulations (6, 7, 8 and 9), were prepared using krill oil orcoconut oil or a mixture of 3 parts of krill oil and 1 part of borageoil, as an oily phase, water as a dispersant, Tween 80 and KolliphorRH40 as emulsifying agents, propylene glycol as a wetting agent, sodiumcitrate dihydrate as a buffer and citric acid as a pH adjuster.

Tween 80, propylene glycol and Kolliphor RH40 are thesurfactants/co-surfactants of the lipid phase, where, in the lipidphase, the Tween 80, the propylene glycol and the Kolliphor RH40 are ina ratio of 1:2:1.5; Kolliphor RH40 and propylene glycol are thesurfactants/co-surfactants of the aqueous phase, where, in the aqueousphase, the Kolliphor RH40 and the propylene glycol are in a ratio of3:1. In formulation 6, the surfactants/co-surfactants of the lipid phaseare 4.05% (w/v) of the microemulsion and the surfactants/co-surfactantsof the aqueous phase are 1.66% (w/v) of the microemulsion. Informulations 7, 8, and 9, the surfactants/co-surfactants of the lipidphase are 18.67% (w/v) of the microemulsion and thesurfactants/co-surfactants of the aqueous phase are 4.15% (w/v) of themicroemulsion.

Microemulsion for Ophthalmic Use, Formulation 6:

Components % w/v Krill oil 0.400 Tween 80 0.900 Kolliphor RH40 3.045Propylene glycol 1.765 Sodium citrate dihydrate 0.500 Citric acid 0.1Nq.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 7:

Components % w/v Coconut oil 1.410 Tween 80 4.150 Kolliphor RH40 11.410Propylene glycol 7.260 Sodium citrate dihydrate 0.500 Citric acid 0.1Nq.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 8:

Components % w/v Krill oil 1.410 Tween 80 4.150 Kolliphor RH40 11.410Propylene glycol 7.260 Sodium citrate dihydrate 0.500 Citric acid 0.1Nq.s. pH 7.40 Purified water q.s. 100ml

Microemulsion for Ophthalmic Use, Formulation 9:

Components % w/v Krill oil 1.060 Borage oil 0.350 Tween 80 4.150Kolliphor RH40 11.410 Propylene glycol 7.260 Sodium citrate dihydrate0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Formulations 10-16

Three formulations (10, 11 and 12) were obtained using a mixturecontaining 3 parts of castor oil and 1 part of oriza sativa bran oil or1 part of avocado oil or 1 part of grape seed oil, as an oily phase,water as a dispersant, Tween 80 and Kolliphor RH40 as emulsifyingagents, propylene glycol as a wetting agent, sodium citrate dihydrate asa buffer and citric acid as a pH adjuster.

Three formulations (13, 14 and 15), were obtained using a mixture of 3parts of krill oil and 1 part of borage oil or 1 part of linseed oil or1 part of chia oil, as an oily phase, water as a dispersant, Tween 80and Kolliphor RH40 as emulsifying agents, propylene glycol as a wettingagent, sodium citrate dihydrate as a buffer and citric acid as a pHadjuster.

Formulation 16 was prepared using coconut oil as an oily phase, water asa dispersant, Tween 80 and Kolliphor RH40 as emulsifying agents,propylene glycol as a wetting agent, sodium citrate dihydrate as abuffer and citric acid as a pH adjuster.

In microemulsion formulations 10, 11, 12, 13, 14, 15 and 16, Tween 80,propylene glycol and Kolliphor RH40 are the surfactants/co-surfactantsof the lipid phase, where, in the lipid phase, the Tween 80, thepropylene glycol and the Kolliphor RH40 are in a ratio of 1:2:1.5;Kolliphor RH40 and propylene glycol are the surfactants/co-surfactantsof the aqueous phase, where, in the aqueous phase, the Kolliphor RH40and the propylene glycol are in a ratio of 3:1. In the formulations, thesurfactants/co-surfactants of the lipid phase are 4.05% (w/v) of themicroemulsion, and the surfactants/co-surfactants of the aqueous phaseare 1.66% (w/v) of the microemulsion.

Microemulsion for Ophthalmic Use, Formulation 10:

Components % w/v Castor oil 0.300 Avocado oil 0.100 Tween 80 0.900Kolliphor RH40 3.045 Propylene glycol 1.765 Sodium citrate dihydrate0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 11:

Components % w/v Castor oil 0.300 Oryza sativa oil 0.100 Tween 80 0.900Kolliphor RH40 3.045 Propylene glycol 1.765 Sodium citrate dihydrate0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 12:

Components % w/v Castor oil 0.300 Grape seed oil 0.100 Tween 80 0.900Kolliphor RH40 3.045 Propylene glycol 1.765 Sodium citrate dihydrate0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 13:

Components % w/v Krill oil 0.300 Borage oil 0.100 Tween 80 0.900Kolliphor RH40 3.045 Propylene glycol 1.765 Sodium citrate dihydrate0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 14:

Components % w/v Krill oil 0.300 Linseed oil 0.100 Tween 80 0.900Kolliphor RH40 3.045 Propylene glycol 1.765 Sodium citrate dihydrate0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 15:

Components % w/v Krill oil 0.300 Chia oil 0.100 Tween 80 0.900 KolliphorRH40 3.045 Propylene glycol 1.765 Sodium citrate dihydrate 0.500 Citricacid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 16:

Components % w/v Coconut oil 0.400 Tween 80 0.900 Kolliphor RH40 3.045Propylene glycol 1.765 Sodium citrate dihydrate 0.500 Citric acid 0.1Nq.s. pH 7.40 Purified water q.s. 100 ml

Table 1 summarizes the ratio between surfactants/co-surfactants in thelipid phase, and the ratio between the surfactants/co-surfactants in theaqueous phase for each of formulations described in this example. Forexample, in formulation 1, there is one surfactant, Tween 80, and oneco-surfactant, propylene glycol in the lipid phase; the amount of Tween80/the amount of propylene glycol is 2:1.

TABLE 1 Ratio surfactants/co-surfactants in the lipid and aqueous phasesSurfactants/co-surfactants Tween Kolliphor Propylene Formulations Phases80 RH 40 glycol 1, 5 Lipid 2 — 1 Aqueous — 3 1 2, 3, 4, 6, 7, 8, 9, 10,Lipid 1 2 1.5 11, 12, 13, 14, 15 and 16 Aqueous — 3 1

Example 2 Influence of Formulation Composition on MicroemulsionParameters and Relative Chemical and Physical Stability

Stress tests were performed on Formulation 1, as described in Example 1,and in its variations subsequently described herein to determinechemical and physical stability.

Formulation 1 was varied using different buffers in amounts andcombinations as set forth Table 2.

TABLE 2 Formulation 1 and relative Total Oily Phase Sodium citrateHistidine Citric Acid Total Aqueous Phase variations (w/v %) (w/v %)(w/v %) 0.1N (w/v %) 1 4.45 0.50 — q.s. pH 7.4 q.s. 100% 1.1 4.45 1.00 —q.s. pH 7.4 q.s. 100% 1.2 4.45 1.00 0.05 — q.s. 100% 1.3 4.45 1.40 0.05— q.s. 100%

The stability data obtained in conditions of thermal shock at 60° C.,for 15 days, are shown in FIGS. 3A-3D and concern: pH (FIG. 3A),osmolality (FIG. 3B), average particle size (size, FIG. 3C) and Zetapotential (pZ, FIG. 3D). From the parameters studied and the results(FIGS. 3A-3D), microemulsion formulation 1, and each of its variations,showed a good stability profile. Of the four microemulsions variants(i.e., 1, 1.1., 1.2 and 1.3), formulation 1, because of its lowercitrate buffer concentration, was selected as the most suitable forophthalmic use and used as a base for further developments andcomparisons.

Varying the ratios between the oily phase and the aqueous phase, and theratio between the surfactants and co-surfactants within the oily andaqueous phase outside the ratios described herein, produces formulationsthat do not have the requisite properties, such as an average particlesize less than 30 nm, or the narrow distribution 15±10 nm. For example,Formulation 5, described above, prepared for comparison withmicroemulsions provided herein, was not formed from aqueous and lipidphases that contained the requisite ratios of surfactants and does notexhibit the advantageous properties of formulations in which the amountof surfactant(s) in each phase meet the requisite criteria. Table 3summarizes differences between microemulsion formulation 1 andformulation 5. Formulation 5 is not within the parameters of themicroemulsions provided herein; it is described herein for the purposeof comparison.

TABLE 3 Formulation 1 Formulation 5 Component (%)(w/v) Quantity(%)(w/v)Oily component 0.40 0.50 Lipid phase surfactants 4.05 5.08 Surfactantsin aqueous phase 1.66 2.62 Dispersant phase q.s. to 100 ml q.s. to 100ml

Specifically, for formulation 1, the ratio between the oily component ofthe lipid phase surfactants-co-surfactants in the aqueous phase is equalto 0.24, which is within the range 0.2-1. For formulation 1, thesurfactant/co-surfactant ratio in the lipid phase tosurfactants/co-surfactants in the aqueous phase is equal to 2.44, whichis within the range 2.0-10. Formulation 1 is characterized by an averageparticle size<20 nm, and a polydispersity index (PDI)<0.10.

For formulation 5, however, the ratio between the oilycomponent/sur-factants-co-surfactants in the aqueous phase is equal to0.19, and the ratio between surfactants/co-surfactants in the lipidphase/surfactants-co-surfactants in the aqueous phase is equal to 1.93.Formulation 5 is characterized by an average particle size >30 nm, and aPDI >0.40.

The average particle distribution diagrams (size) for formulation 1 andformulation 5 are shown in FIGS. 4A and 4B, respectively. Formulation 5appears opalescent and is thermodynamically unstable. In contrast,formulation 1, and its variants described herein, appeared transparentand are thermodynamically stable in the studies carried out for a periodof up to 6 months.

FIGS. 5A-5D show the stability data of formulation 1 in time (months)relating to osmolality (FIG. 5A), pH (FIG. 5B), average particle size(nm, FIG. 5C), and Zeta potential (pZ, FIG. 5D) at 25° C. and 40° C.These results show that any deviation from the requisite ratiosdescribed herein results in microemulsions that do not have theadvantageous properties. Thus, provided are parameters and componentsfor preparing microemulsions that have properties that have notheretofore been observed.

Example 3 Stability of Formulation 4

FIGS. 6A-6C show the stability data in time (months) relating to sizeand the PDI at different temperatures [25° C. (FIG. 6A), 40° C. (FIG. B)and 60° C. (FIG. 6C)] of an illustrative microemulsion formulationprovided herein. In each of the conditions analyzed, formulation 4always presents a size and a PDI within 15±10 nm and 0.070±0.050,respectively. Such values are within the ranges provided herein, andremained constant for the whole study period.

Example 4 Stability of Formulations 7, 8, and 9

Formulations 7, 8, and 9 are characterized by: size≥25 nm;polydispersity index (PDI)≥0.24 and pH value within the range 6.0-7.4.

FIGS. 7A-7D show the stability data of formulations 7, 8 and 9 in time(weeks) relating to pH (FIG. 7A), average particle size (nm, FIG. 7B),polydispersity index (PDI, FIG. 7C) and Zeta potential (mV, FIG. 7D) inconditions of thermal shock at 60° C., for 30 days.

In the condition analyzed, all formulations always show a size and a PDIwithin the ranges 15±10 nm and 0.190±0.050, respectively. Such valuesare within the ranges provided herein, and remain constant for the wholestudy period.

Example 5

Stability of Formulations 6, 10, 11, 12, 13, 14, 15 and 16

Formulation 6 is characterized by: size<20 nm; polydispersity index(PDI)<0.10 and pH value within the indicated ranges of 5-6.

Formulations 10, 11, 12, 13, 14, 15 and 16 are characterized by: size<20nm; polydispersity index (PDI)<0.10 and pH value within the indicatedranges of 6.5-7.5.

FIGS. 8A-8E show the stability data in time (weeks) relating to pH (FIG.8A), average particle size (nm, FIG. 8B), polydispersity index (FIG.8C), osmolality (FIG. 8D) and Zeta potential (mV, FIG. 8E) in conditionsof thermal shock at 60° C., for 30 days.

In the condition analyzed, all formulations always show a size and a PDIwithin the ranges 15±10 nm and 0.190±0.050, respectively.

Such values are within the range provided herein and remain constant forthe whole study period.

Summary Table of Some of the Exemplary Microemulsion FormulationsComponent Target Formulation Amounts w/v % ratios 3 05^(c) 7 8 5^(d) 1 4Oil^(a) 4 1.41 1.41 1.41 0.5 0.4 0.4 (coconut (krill oil) oil) Tween ®80 8 4.15 4.15 4.15 3.39 2.7 0.9 Kolliphor ® RH40 19.11 11.41 11.4111.41 1.97 1.25 3.05 Propylene glycol 13.04 7.26 7.26 7.26 2.35 1.771.77 Total surfactant(s) and co- 40.15 22.82 22.82 22.82 7.71 5.71 5.71surfactant(s) ratio between surfactant(s) 2-10 8.67 4.51 4.51 4.51 1.942.44 2.43 and co-surfactant(s) in the lipid phase and in the aqueousphase^(d) weight/volume ratio 0.2 to 0.96 0.34 0.34 0.34 0.19 0.24 0.24between oil and the 1.0 surfactant(s) and co- surfactant(s) in theaqueous phase^(d) Stability^(b) n.d. n.d. S S NS S S ^(a)Oil isIsopropyl myristate unless otherwise indicated ^(b)n.d. = not described,S = stable, NS = not stable ^(c)Formulation 05 contains a drug -seeExample 6 ^(d)outside the ratios

Example 6 Exemplary Microemulsions Containing Latanoprost, Masoprocol orSorafenib Tosylate

Formulations that contain a pharmaceutically active compound aredesignated with a “0” in front of the number. Five formulations,designated 01, 02, 03, 04 and 05, prepared as described herein, containisopropyl myristate as an oily component, water as a dispersant, Tween80 and Kolliphor RH40 as emulsifying agents, propylene glycol as awetting agent, and sodium citrate dihydrate and/or histidinehydrochloride as a buffer.

Four formulations, designated 06, 07, 08 and 09, contain krill oil orcoconut oil or 3 parts of krill oil and 1 part of borage oil, as an oilyphase, water as a dispersant, Tween 80 and Kolliphor RH40 as emulsifyingagents, propylene glycol as a wetting agent, sodium citrate dihydrateand/or histidine hydrochloride as a buffer.

The following tables provide exemplary microemulsions that include anactive agent for ophthalmic use.

Microemulsion for Ophthalmic Use, Formulation 01:

Components % w/v Latanoprost 0.005 Isopropyl myristate 0.400 Tween 802.700 Kolliphor RH40 1.245 Propylene glycol 1.765 Sodium citratedihydrate 0.500 Histidine HCl 0.015 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 02:

Components % w/v Latanoprost 0.005 Isopropyl myristate 0.400 Tween 802.700 Kolliphor RH40 1.245 Propylene glycol 1.765 Sodium citratedihydrate 0.700 Histidine HCl 0.030 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 03:

Components % w/v Latanoprost 0.005 Isopropyl myristate 0.400 Tween 802.700 Kolliphor RH40 1.245 Propylene glycol 1.765 Sodium citratedihydrate 0.500 Citric acid 0.1N q.s. pH 7.40 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 04:

Components % w/v Masoprocol 0.302 Isopropyl myristate 0.400 Tween 802.700 Kolliphor RH40 1.245 Propylene glycol 1.765 α-Tocopherol 0.100Sodium citrate dihydrate 0.500 Citric acid 0.1N q.s. pH 5.50 Purifiedwater q.s. 100 ml

In formulations 01, 02, 03 and 04, Tween 80 and propylene glycol are thesurfactants/co surfactants of the lipid phase, where, in the lipidphase, the Tween 80 and the propylene glycol are in a ratio of 2:1;Kolliphor RH40 and propylene glycol are the surfactants/co-surfactantsof the aqueous phase, where, in the aqueous phase, the Kolliphor RH40and the propylene glycol are in a ratio of 3:1. In formulation 1, thesurfactants/co-surfactants of the lipid phase are 4.05% (w/v) of themicroemulsion and the surfactants/co-surfactants of the aqueous phaseare 1.66% (w/v) of the microemulsion.

Microemulsion for Ophthalmic Use, Formulation 05:

Components % w/v Sorafenib tosylate 0.300 Isopropyl myristate 1.410Tween 80 4.150 Kolliphor RH40 11.410 Propylene glycol 7.260 Sodiumcitrate dihydrate 0.500 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 06:

Components % w/v Masoprocol 0.302 Krill oil 0.400 Tween 80 0.900Kolliphor RH40 3.045 Propylene glycol 1.765 α-Tocopherol 0.100Resveratrol 0.050 Sodium citrate dihydrate 0.500 Citric acid 0.1N q.s.pH 5.20 Purified water q.s. 100 ml

In formulation 06, Tween 80, propylene glycol and Kolliphor RH40 are thesurfactants/co-surfactants of the lipid phase, where, in the lipidphase, the Tween 80, the propylene glycol and the Kolliphor RH40 are ina ratio of 1:2:1.5; Kolliphor RH40 and propylene glycol are thesurfactants/co-surfactants of the aqueous phase, where, in the aqueousphase, the Kolliphor RH40 and the propylene glycol are in a ratio of3:1. In the formulations, the surfactants/co-surfactants of the lipidphase are 4.05% (w/v) of the microemulsion and thesurfactants/co-surfactants of the aqueous phase are 1.66% (w/v) of themicroemulsion.

Microemulsion for ophthalmic use, formulation 07:

Components % w/v Sorafenib tosylate 0.300 Coconut oil 1.410 Tween 804.150 Kolliphor RH40 11.410 Propylene glycol 7.260 Sodium citratedihydrate 0.500 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 08:

Components % w/v Sorafenib tosylate 0.300 Krill oil 1.410 Tween 80 4.150Kolliphor RH40 11.410 Propylene glycol 7.260 Sodium citrate dihydrate0.500 Purified water q.s. 100 ml

Microemulsion for Ophthalmic Use, Formulation 09:

Components % w/v Sorafenib tosylate 0.300 Krill oil 1.060 Borage oil0.350 Tween 80 4.150 Kolliphor RH40 11.410 Propylene glycol 7.260 Sodiumcitrate dihydrate 0.500 Purified water q.s. 100 ml

In formulations 05, 07, 08 and 09, Tween 80, propylene glycol andKolliphor RH40 are the surfactants/co-surfactants of the lipid phase; inthe lipid phase, the Tween 80, the propylene glycol and the KolliphorRH40 are in a ratio of 1:2:1.5; Kolliphor RH40 and propylene glycol arethe surfactants/co-surfactants of the aqueous phase, where, in theaqueous phase, the Kolliphor RH40 and the propylene glycol are in aratio of 3:1. In these formulations, the surfactants/co-surfactants ofthe lipid phase are 18.67% (w/v) of the microemulsion and thesurfactants/co-surfactants of the aqueous phase are 4.15% (w/v) of themicroemulsion (total surfactants/co-surfactants in the resultingmicroemulsion are 23.83%).

Example 7 Stability of Formulations 01, 02 and 03 of Example 6Containing Latanoprost

Formulations 01, 02 and 03 as described in Example 6 were subjected tostress tests to evaluate their chemical and physical stability. Thestability data obtained in thermal shock conditions at 60° C. for 15days is shown in FIGS. 9A-9E, which shows: pH (FIG. 9A), osmolality(FIG. 9B), size (FIG. 9C), pZ (FIG. 9D) and percentage of latanoprostrecovery (FIG. 9E).

All of the tested formulations were shown to maintain chemical-physicalparameters within the specifications during the whole of the studyperiod. Formulation 03 highlighted a low variability in the percentageof latanoprost and an osmolality value more suitable for ophthalmic use.

A stability study was performed on formulation 03 for up to 24 months.The results are shown in FIGS. 10A-10E and FIGS. 11A-11D. The stabilitydata obtained at 25° C., 40° C. and 5° C. is shown in FIGS. 10A-E, whichshows: pH (FIG. 10A), osmolality (FIG. 10B), size (FIG. 10C), and pZ(FIG. 10D). In FIG. 10E, the graph shows the concentration oflatanoprost in the long-term stability study (25° C.±2° C., RH=60%±5%),expressed as recovery % according to the different study times. Theconcentration of latanoprost stayed within the specification limits forthe whole duration of the analysis. FIG. 11A shows the PDI and theaverage particle size distribution determined during the course of thelong-term stability study (25° C.±2° C., RH=60%±5%). FIGS. 11B-11D showthe PDI and the average particle size determined at 40° C. for 6 months,60° C. for 3 weeks, and 4° C. for just over 10 months, respectively. Themeasured parameters were within the expected ranges for the duration ofthe study.

Example 8 Stability of Formulations 04 and 06 of Example 6, ContainingMasoprocol

Formulations 04 and 06 as described in Example 6 were subjected to longterm stability studies to evaluate their stability profiles (25° C.±2°C., RH=60%±5%, 5° C.±3° C.). FIGS. 12A-12E show the pH (FIG. 12A),osmolality (FIG. 12B), size (FIG. 12C), pZ (FIG. 12D) and percentage ofmasoprocol recovery (FIG. 12E) determined during the course of thelong-term stability study. The measured parameters remained within theexpected ranges for the duration of the study.

Example 9 Stability of Formulations 07, 08, and 09

Formulations 07, 08 and 09, which contain sorafenib tosylate, asdescribed in Example 6 were subjected to stress tests and long-termstability tests to evaluate their stability.

FIGS. 13A-13E show the pH (FIG. 13A), size (FIG. 13B), polydispersityindex (FIG. 13C), pZ (FIG. 13D) and percentage of sorafenib recovery(FIG. 13E) determined during the course of the long-term stability study(25° C.±2° C., RH=60%±5%) and accelerated stability study (40° C.±2° C.,RH=75%±5%). All formulations in both conditions showed parameters withinthe expected ranges for the whole duration of the study. In particular,formulation 07 exhibited very low variability in the pH value in theaccelerated condition study.

Example 10 Cell Viability in Statens Seruminstitut Rabbit Cornea (SIRC)Cells

SIRC cells were allowed to grow at 37° C., 5% CO2 in complete BasalMedium Eagle (BME) until subconfluence (70-90%) and then repeatedlyexposed (6×5 min) to control formulations or microemulsions at differentconcentrations (%) (see Table 4). Cells were also exposed to negativecontrol (sterile culture medium containing fetal bovine serum-free BME,CTRL−) and positive control (benzalkonium chloride 0.01%, CTRL+) forcytotoxicity. Analysis of cell viability was conducted by3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT)assay using the ECVAM Protocol n° 17. The optical density (O.D.) wasread at 570 nm in a microplate spectrophotometer. Cell viability wascalculated as a percentage of negative control and statistical analysiswas performed with one sample t-test vs. cut-off 50%.

TABLE 4 Microemulsions and relative active ingredient. MicroemulsionMicroemulsion Active ingredient % concentration Formulation 1 None 100,20, 10, 5, 2.5 Formulation 04 masoprocol 0.302% Formulation 2 NoneFormulation 05 sorafenib tosylate 0.300% Formulation 6 None Formulation06 masoprocol 0.302% Formulation 7 None Formulation 07 sorafenibtosylate 0.300% Formulation 8 None Formulation 08 sorafenib tosylate0.300% Formulation 9 None Formulation 09 sorafenib tosylate 0.300%Formulation 10 None Formulation 11 None Formulation 12 None

Viability assessed by means of MTT demonstrated that no cellularmortality was associated with the microemulsions with or without activeingredient in any of the conditions tested (data not shown).Microemulsions containing vegetable and/or animal oils showed bettercytocompatibility than the microemulsions containing mineral oils ofsynthetic origin.

Example 11 Efficacy In Vivo in a Chronic Ocular Hypertension Model

An in vivo pharmacological study was carried out on a chronic ocularhypertension model induced by means of cauterization of the episcleralveins (EVC) in rat. The hypotensive effect of the microemulsioncontaining latanoprost 0.005% (formulation 03) described in Example 6was evaluated by administering one drop per day during the course of atreatment cycle lasting six days.

The latanoprost formulated in the microemulsion (formulation 03)produced an average reduction in intraocular pressure of 3.3 mmHg [n=15,95% CI (2.9, 3.7)]. As is shown in FIG. 14, this effect was comparable(p>0.05, Student t-test) to the effect in the eye treated with astandard solution of latanoprost 0.005% (solution) [n=11, 3.6 mmHg, 95%CI (3.2, 4.1)].

Example 12 Efficacy in the Retinal Ischemia-Reperfusion Model

A retinal ischemia-reperfusion (IR) model in rat was used to demonstratethe in vivo efficacy of the microemulsions containing masoprocol 0.302%(microemulsions formulations 04 and 06) and the microemulsionscontaining sorafenib tosylate 0.300% (microemulsions formulations 05 and07), shown in Example 6. Before inducing the IR, Brown-Norway adult malerats weighing 200-250 g were treated topically for 2 days (12 μl b.i.d.,right eye) and 1h before the insult (12 μl, right eye) with one of thefollowing formulations: a) formulation 1; b) formulation 04; c)formulation 6; d) formulation 06; e) formulation 2; f) formulation 05;g) formulation 7 or h) formulation 07. Animals were anaesthetized, and,following mydriasis induced by tropicamide 0.5%, the IR was induced byinserting a 30 gauge needle into the front chamber of the right eye,connected to a container of physiological saline solution. The salinesolution reservoir was positioned at a height from the operating tablethat guaranteed hydrostatic pressure at the eye level of approximately130 mmHg. Raising intraocular pressure to such levels to induce theischemia was confirmed by the “whitening” of the back of the eye. After45 min, the needle was removed to restore the retinal blood flow.

Six hours after the ischemic episode, the animals were sacrificed andthe retinas taken and preserved in 50 μl of storage stabilizationsolution (RNAlater®, available from ThermoFisher Scientific) to evaluateany potential effects of the microemulsions containing masoprocol 0.302%(formulations 04 and 06) or the microemulsions containing sorafenibtosylate 0.300% (formulations 05 and 07) on the pro-inflammatory geneexpression by means of Real Time RT-PCR.

Analysis of the gene expression levels in the retinas of rats treatedwith microemulsions containing masoprocol 0.302% showed that: a)treatment with formulation 04 significantly reduced the TNF-alpha(28.7%) and iNos (130%) expression levels (# p≤0.05, ## p≤0.01) comparedto that observed in the retinas of animals treated with the carrieralone (formulation 1; see FIG. 15A); b) treatment with formulation 06significantly reduced the expression levels of TNF-alpha (49.5%) andiNos (82.4%) (# p≤0.05, ## p≤0.01) compared to that observed in theretinas of animals treated with the carrier alone (formulation 6; seeFIG. 15B).

Treatment of ischemic rats with microemulsions containing sorafenibtosylate 0.300% showed that: a) formulation 05 significantly reduced theexpression levels of the mRNA of TNF-alpha (20.7%) and iNos (87.3%) (#p≤0.05, ## p≤0.01) compared to that observed in retinas of animalstreated with the carrier alone (formulation 2; see, FIG. 16A); b)treatment with formulation 07 significantly reduced the expressionlevels of TNF-alpha (45.3%) and iNos (96.5%) (# p≤0.05, ## p≤0.01)compared to what was observed in retina of animals treated with thecarrier alone (formulation 7; see FIG. 16B).

Microemulsions comprising vegetable (formulation 07) and/or animal(formulation 06) oils showed an efficacy profile superior to that shownby microemulsions comprising mineral oils of synthetic origin(formulations 04 and 05).

Example 13 Efficacy in a Murine Model of Choroidal Neovascularization

In order to evaluate the potential anti-angiogenic action of themicroemulsion containing masoprocol 0.302% (formulation 04) and themicroemulsions containing sorafenib tosylate 0.300% (formulations 05 and07) in age-related macular degeneration (AMD), a murine model ofchoroidal neovascularization (CNV) was used. For this purpose, 6-8week-old male mice C57B16/J were pre-treated topically (5 μl b.i.d.,both eyes) for three days preceding the induction of CNV and for thefollowing 7 days with one of the following formulations: a) formulation1; b) formulation 04; c) formulation 2; d) formulation 05; e)formulation 7 or f) formulation 07.

Before laser induction, the animals were anaesthetized byintraperitoneal injection with a solution of ketamine and xylazine (80mg/Kg and 10 mg/Kg, respectively) and the pupil dilated with a topicalapplication of 0.5% tropicamide. Subsequently, an aqueous solution of2.5% hydroxy-propyl-methylcellulose was introduced into both eyes. Theeyeground was observed with a camera and photocoagulation was inducedusing an image-guided laser system (Micron IV, Phoenix ResearchLaboratories, Pleasanton Calif.). Four radial spots were performed inboth eyes at an equal distance from the optic nerve by laser impulse(532 nm; duration 100 msec; power 200 mW). The neovascularization areawas determined by means of an immunofluorescence test. The animals weresacrificed by cervical dislocation and the enucleated eyes were put in4% paraformaldehyde, then, the front segment of the eye was removed andthe remaining part, called the ‘eye-cup’ (sclera, choroid, retinalpigment epithelium [RPE] and retina), was incubated in the presence of0.7% FITC-Griffonia simplicifolia Isolectin for 16h. The volume of eachspot was obtained by fluorescence acquisition of a stack of images(20-25 frames, each with a thickness of 1-μm) along the z axis, from theupper surface to the deepest focal plane, in relation to the RPE cells.The fluorescent areas of each frame composing a single stack weremeasured with the program Image) (NIH, Bethesda, Md.) and addedtogether, thus obtaining a neovascularization volume measurement.

The results demonstrate that animals treated topically with themicroemulsion containing masoprocol 0.302% (formulation 04) showed astatistically significant reduction in choroidal neovascularization of˜33% (p=0.0395) compared to carrier alone (formulation 1) (FIG. 17). Theresults also demonstrate that animals treated topically with themicroemulsion containing sorafenib tosylate 0.300% (formulation 05)showed a 54% reduction of choroidal neovascularization; this result washighly significant when compared to animals treated with carrier alone(formulation 2) (FIG. 18A). Similar results have been obtained inanimals treated topically with formulation 07, which significantlyreduced choroidal neovascularization by ˜61% (p=0.0001) when compared tocarrier alone (formulation 7) (FIG. 18B).

The microemulsion containing vegetable oils and containing sorafenibtosylate 0.300% (formulation 07) showed an efficacy profile superior tothat observed for the microemulsion comprising mineral oils of syntheticorigin (formulation 05).

Example 14 Efficacy in the Streptozotocin-Induced Diabetic RetinopathyModel

Experiments were designed and conducted to assess the efficacy of themicroemulsion containing masoprocol 0.302% (formulation 04) and of themicroemulsion containing sorafenib tosylate 0.300% (formulation 05) in amodel of the streptozotocin (STZ)-induced diabetic retinopathy in rat.To this end, Sprague-Dawley male rats (200-250 g) were injected with asingle dose of STZ (60 mg/kg i.p.) and 24h later, the blood glucose wasmeasured to include in the rest of the procedure only animals withglycaemia levels higher than 250 mg/dl. Starting from the day when theglycaemia was measured, the animals were treated for 21 days in botheyes b.i.d. and divided into the following treatment groups:

-   -   negative control rats (ctrl-) and diabetic rats (STZ) treated        with 12 μl of formulation 1 or formulation 2; and    -   diabetic rats treated with 12 μl of formulation 04 or        formulation 05.

At the end of the treatment course, animals were sacrificed, the bulbsenucleated and the retinas processed for performing gene and proteinexpression tests by Real Time RT-PCR and Western Blot, respectively.

Gene expression analysis by Real Time RT-PCR demonstrated that, whencompared to STZ-treated animals, treatment with the microemulsioncontaining masoprocol 0.302% (formulation 04) (FIGS. 19A-19F) orcontaining sorafenib tosylate 0.300% (formulation 05) (FIGS. 19A-19F)significantly reduced the expression levels of the proinflammatory andpro-angiogenic genes analyzed (i.e. TNFa, NFκB, IGF1, IGF1R, VEGFR1 andVEGFR2).

Protein expression analysis by Western Blot showed that treatment withformulation 04 (FIGS. 20A-D) or formulation 05 (FIGS. 20E-H)significantly reduced the expression levels of TNFa, VEGFR1 and VEGFR2compared to the retinas of the STZ-induced animals, thus confirming theanti-inflammatory and anti-angiogenic effect of both microemulsionsformulated as described herein (FIGS. 20A-H).

Example 15 Ocular Tolerability In Vivo

A long-term tolerability study was carried out on New Zealand Whiterabbits (NZW) to assess ocular tolerability over a 28-day topicalrepeated-treatment course of the following microemulsions: a)formulation 1, b) formulation 04, c) formulation 6, d) formulation 06,e) formulation 2, f) formulation 05, g) formulation 7, or h) formulation07.

Forty-eight rabbits were used, 24 males and 24 females, weighingapproximately 2 Kg, and randomized into 8 experimental groups, each ofwhich was composed of 6 animals (3 males and 3 females). In order tomimic the human dosing regimen, 50 μl of the formulations or of thevehicle (Tris pH 7.4) were administered b.i.d. by instillation into theconjunctival sac of the right (treated) or left (vehicle) eye,respectively.

The tolerability of the microemulsions studied was determined by meansof the Draize test modified by McDonald et aL, 1987 (Eye irritation, inDermatotoxicology, Ed. Marzulli and Maibach, Hemisphere PublishingCorporation, 3rd Edition). Statistically significant differences weresought by means of General Linear Model analyses and unpaired t-test.Scores assigned using the modified Draize test did not evidence anydifference among the sexes for any of the treatment groups.

Statistics show that there were no significant differences between thetreated eye (right) and the control eye (left) in any of the treatmentgroups. There were no differences among microemulsion formulationscontaining the drugs (i.e., loaded microemulsions) and the relativevehicle (i.e. unloaded microemulsions).

The microemulsions based on vegetable and/or animal oils showed a betterocular tolerability profile than microemulsions comprising mineral oilsof synthetic origin.

Example 16 Efficacy in a Murine Model of Dry Eye

A murine model of dry eye was used to establish the efficacy of themicroemulsion containing masoprocol 0.302% (formulation 04), describedin Example 6. To this end, C57BL/6 female mice (8-12 weeks old), wereexposed for 3 days to a controlled environmental chamber (CEC) under lowhumidity (<20% RH; 21-22° C.) and constant airflow (20 L/min). Inaddition to the environmental conditions, 5 mg/ml of scopolamine wasinjected subcutaneously three times a day for 3 days. At the same time,a group of negative control animals (CTRL−) were kept in standardenvironmental conditions (21-23° C.; 50-60% RH).

Mice inside the CEC were divided into three groups: i) treated withformulation 1; ii) treated with formulation 04; and iii) un-treatedpositive control group (CTRL+). Seven microliters of the test items wereinstilled in both eyes twice daily for 3 days; animals outside the CEC,i.e. CTRL−, were left untreated for the entire duration of the study.

Fluorescein staining of the cornea was evaluated by slit lamp with astandardized grading system at baseline (t=0) and after 3 days oftreatment (T3), to evaluate the corneal damage. The animals weresacrificed at T3 and the cornea excised and preserved for furtherprocessing aimed at evaluating potential effects of the treatments onpro-inflammatory gene expression by Real Time RT-PCR.

Observations at T3 showed that corneal staining of CTRL+ mice wassignificantly worsened (p≤0.0001) with respect to CTRL-. Treatment withformulation 1 did not produce any remarkable amelioration over CTRL+,while formulation 04 significantly reduced corneal score (p<0.05, vsCTRL+) (FIG. 21).

Analysis of gene expression showed that treatment with formulation 04significantly reduced TNFa expression levels by 58% compared toCTRL+animals (# p<0.05, vs CTRL+) (FIG. 22). The microemulsioncontaining masoprocol 0.302% (formulation 04) was effective in reducingocular signs in a murine model of dry eye, a pathology of the ocularsurface.

Since modifications will be apparent to those of skill in this art, itis intended that this invention be limited only by the scope of theappended claims.

1. A pharmaceutical composition that is an oil-in-water microemulsion,comprising: a) a lipid phase comprising an oily component and one ormore surfactant(s) and, one or more co-surfactant(s); b) an aqueousphase comprising one or more surfactant(s), and one or moreco-surfactants; and c) a pharmaceutically active compound, wherein: theweight/volume ratio between the total amount of surfactant andco-surfactant in the lipid phase to the total amount of surfactant andco-surfactant in the aqueous phase is from 2 to 10; the weight/volumeratio between the amount of oily component in the lipid phase to thetotal amount of surfactant and co-surfactant in the aqueous phase isfrom 0.2 to 1.0; and in the resulting oil-in-water microemulsion, theaverage particle size is less than 30 nm.
 2. The composition of claim 1,wherein: the size distribution of particles in the resultingmicroemulsion is 15 nm±10 nm; and the polydispersity index (PDI) iswithin the range 0.02-0.380, inclusive, or 0.02 to 0.2, inclusive, or0.02 to 0.15, inclusive, or is less than 0.2 or less than 0.12 or lessthan 0.1.
 3. The composition of claim 1, wherein: the weight/volumeratio between the total amount of surfactant and co-surfactant in thelipid phase to the amount of surfactant and co-surfactant in the aqueousphase is 2.2 to 9.8, inclusive, or 2.4 to 8.6, inclusive; theweight/volume ratio between the amount of oily component in the lipidphase to the amount of surfactant(s) and co-surfactant(s) in the aqueousphase is from 0.22 to 0.98, inclusive or from 0.24 to 0.96, inclusive;and in the lipid phase, the weight/volume ratio between the oilycomponent and the surfactant(s) and co-surfactant(s) is from 0.05 to1.4, inclusive.
 4. The composition of claim 3, wherein, in the lipidphase, the weight/volume ratio between the oily component and thesurfactant(s) and co-surfactant(s) is from 0.07 to 1.2, inclusive, orfrom 0.1 to 1, inclusive.
 5. The pharmaceutical composition of claim 1,wherein: the pharmaceutically active compound is an ophthalmic drug; andthe composition is formulated for treatment of ophthalmic conditions ordisorders.
 6. A composition of claim 1, comprising: an oily component inan amount of 0.4%-4.0% weight/volume (w/v) of the composition; asurfactant or a mixture of a surfactant(s) and co-surfactants(s) in anamount of 5.71%-40.15% (w/v), inclusive, of the composition; an aqueouscomponent that is in an amount between 55.85%-93.89% (w/v), inclusive,of the composition; and a pharmaceutically active compound in an amountbetween 0.001 mg/ml to 50 mg/ml, inclusive, wherein: all components ofthe composition are biocompatible; and the average particle size in themicroemulsion composition is less than 30 nm.
 7. The composition ofclaim 1, wherein the surfactant(s) and co-surfactant(s) are nonioniccompounds with an Hydrophobic-Lipophilic Balance (HLB) between 8-16,inclusive.
 8. The composition of claim 1 that contains one surfactantand one co-surfactant, or two surfactants and one co-surfactant, or twosurfactants and two co-surfactants.
 9. The composition of claim 1,wherein a surfactant in the lipid phase and the aqueous phase is thesame and/or the surfactant in the aqueous and lipid phase is differentand/or the co-surfactant in the aqueous and lipid phase is the sameand/or the co-surfactant in the aqueous and lipid phase is different.10. The composition of claim 1, wherein the co-surfactant(s) is/areglycerol and/or propylene glycol.
 11. The composition of claim 1,wherein the surfactants are selected from among poloxamers, PEGylatedfatty acids, polyoxyethylene sorbitan fatty acid derivatives,polyoxyethylenes, hydrogenated castor oil ethoxylates, glycerol estersof fatty acids, polyoxyl castor oil surfactants, amine oxides, andalcohol ethoxylates (nonionic).
 12. The composition of claim 1, whereinthe surfactants are selected from among polyethylene glycol,polyethylene glycol sorbitan monolaurate (polysorbate 20; TWEEN 20),polyethylene glycol sorbitan monooleate (polysorbate 80; TWEEN 80),polyethylene glycol sorbitan monopalmitate (polysorbate 40; MONTANOX40), lecithin, polyoxyl 35 castor oil (CREMOPHOR EL, KOLLIPHOR EL),polyoxyl 40 hydrogenated castor oil (CREMOPHOR RH40; KOLLIPHOR RH 40),PEG 40 castor oil (ETOCAS 40), PEG-60 hydrogenated castor oil (CRODURET60), and polyethylene glycol 15-hydroxy-stearate (KOLLIPHOR HS 15). 13.The composition of claim 1, comprising one or more of an isotonizing(tonicity) agent, stabilizing agent, anti-oxidant, anti-microbial,thickening agent, and branched and linear polymers.
 14. The compositionof claim 1, wherein the lipid phase contains TWEEN 80/propylene glycolor TWEEN 80/Kolliphor RH40/propylene glycol as thesurfactant(s)/co-surfactant, and the aqueous phase contains KolliphorRH40/propylene glycol as the surfactant/co-surfactant.
 15. Thecomposition of claim 1 comprising one or more vegetable, animal orsynthetic mineral oils selected from among soya oil, corn oil, linseedoil, sunflower seed oil, krill oil, cod-liver oil, fish oil, avocadooil, almond oil, babassu oil, borage oil, carob oil, cashew nut oil,grapeseed oil, coconut oil, Oryza sativa bran oil, castor oil, hemp seedoil, jojoba oil, peanut oil, poppy seed oil, sesame oil, walnut oil,olive oil, wheat-germ oil, argan oil, cottonseed oil, blackcurrant seedoil, oils rich in PUFAs by a fraction greater than 10%, esters of mediumand long-chain fatty acids, and medium and long-chain triglycerides. 16.The composition of claim 1, wherein the pharmaceutically active compoundis selected from among one or more, gastrointestinal agents,antispasmodics, blood sugar regulators,nutraceuticals/minerals/electrolytes, platelet modifying agents,coagulants, cardiovascular agents, alpha-adrenergicagonists/alpha-adrenergic antagonists/vasodilators/arterialvasodilators, carbonic anhydrase inhibitor diuretics/loopdiuretics/potassium-sparing diuretics/thiazide diuretics, othercardiovascular agents, beta-adrenergic antagonists, calcium channelblockers, angiotensin converting enzyme (ACE) inhibitors,dyslipidemics/HMG CoA Reductase inhibitors (Statins), anti-fungals,dermatological agents, anti-histamines, anesthetics, anti-bacterials,hormone-stimulating agents/substituents/modifiers (adrenals, pituitaryand sex hormones), glycemic agents, hormone-suppressing agents(parathyroids), anti-mycobacterial s, anti-virals, anti-neoplastics,immunomodulators, anti-inflammatory agents, analgesics,anti-convulsants, anti-Parkinson agents, anti-psychotics,anti-depressants/anti-dementia agents/anti-anxiety medication,anti-myasthenic agents/agents for treating substances of abuse/centralnervous system agents,bronchodilators/sympathomimetics/anti-cholinergics/inhaledcorticosteroids/phosphodiesterase inhibitors/airborne disorders, otheragents of the respiratory tract, anti-parasites, anti-glaucomaophthalmic agents, other ophthalmic agents/anti-allergic ophthalmicagents, ophthalmic anti-inflammatories, prostaglandin analogues andophthalmic prostamides, drugs for acidity-related disorders, drugs forgastrointestinal function disorders, drugs used for diabetes, vitamins,mineral supplements, antithrombotic agents, anti-hemorrhagics, cardiactherapy drugs, anti-hypertensives, diuretics, peripheral vasodilators,vasoprotectives, beta-blocking agents, calcium-antagonists, drugs actingon the renin-angiotensin system, lipid-lowering drugs, anti-fungals fordermatological use, emollients and protectives, drugs for injuries andulcers, antipruritics, including anti-histamines, anaesthetics,anti-psoriasis drugs, antibiotics and chemotherapeutic agents fordermatological use, antiseptics and disinfectants, hyphophyseal,hypothalamic hormones and similar, systemic corticosteroids, thyroidtherapy, pancreatic hormones, homeostatic calcium, anti-bacterials forsystemic use, anti-mycotics for systemic use, anti-mycobacterials,anti-viral drugs for systemic use, immune serums and immunoglobulins,anti-neoplastic agents, endocrine therapy, immunostimulants,immunosuppressants, anti-inflammatories and anti-rheumatics, topicalproducts for joint and muscle pain, anesthetics, analgesics,anti-epileptics, anti-parkinsonians, psycholeptics, psychoanaleptics,other nervous system drugs, rhinologic preparations, preparations forthe pharyngeal cavity, drugs for obstructive disorders of therespiratory tract, preparations for coughs and colds, anti-histaminesfor systemic use, other preparations for the respiratory system,anti-infectives, anti-inflammatory agents, anti-inflammatory agents andanti-infectives combined, anti-glaucoma agents and miotics, mydriaticsand cyclopegics, decongestants and anti-allergens, local anaesthetics,diagnostic agents, surgical aids, ocular vascular agentsanti-infectives, corticosteroids, and corticosteroids combined withanti-infectives combined.
 17. The composition of claim 1, wherein: thepharmaceutically active compounds are for treating ophthalmic disorders;and the disorders are selected from among dry eye, macular degeneration,glaucoma, infection, inflammation, allergy and diabetic retinopathy. 18.The composition of claim 17, wherein the pharmaceutically activecompound is selected from among a prostaglandin inhibitor, ananti-angiogenic, and an anti-oxidant.
 19. The composition of claim 18,wherein the pharmaceutically active compound is a prostaglandininhibitor selected from among latanoprost, travoprost, bimatoprost,unoprostone, and pharmaceutically acceptable derivatives, hydrates,solvates, metabolites and salts thereof, or a polymorphic crystallineform thereof.
 20. The composition of claim 18, wherein thepharmaceutically active compound is an anti-angiogenic agent selectedfrom among sorafenib, sorafenib tosylate, regorafenib, regorafenibtosylate, regorafenib isethionate, regorafenib ethylsulfonate,apremilast, radotinib, spironolactone, and pharmaceutically acceptablederivatives, hydrates, solvates, metabolites and salts thereof, or apolymorphic crystalline form thereof.
 21. The composition of claim 18,wherein the pharmaceutically active compound is an anti-oxidant selectedfrom among nordihydroguaiaretic acid, meso-nordihydroguaiaretic(masoprocol) and pharmaceutically acceptable derivatives, hydrates,solvates, metabolites and salts thereof, or a polymorphic crystallineform thereof.
 22. The composition of claim 1, wherein thepharmaceutically active compound is at a concentration of from 0.001mg/ml to 50 mg/ml, inclusive, or 0.01 to 30 mg/ml, inclusive, or 0.01 to50 mg/ml, inclusive.
 23. A method of treatment of an ophthalmicdisorder, comprising administering a composition of claim
 5. 24. Themethod of claim 23, wherein the ophthalmic disorder or condition is dryeye, macular degeneration, glaucoma, infection, inflammation, allergy ordiabetic retinopathy.
 25. The method of claim 24, wherein thepharmaceutically active compound in the microemulsion composition ismasoprocol, sorafenib tosylate, and/or latanoprost.
 26. A method forpreparing a microemulsion, comprising: a) preparing a lipid phasecomprising an oily component and a surfactant and, a co-surfactant(s);and b) preparing an aqueous phase comprising a surfactant(s), and aco-surfactant(s), wherein: the weight/volume ratio between the totalamount of surfactant and co-surfactant in the lipid phase to the totalamount of surfactant and co-surfactant in the aqueous phase is from 2 to10; and the weight/volume ratio between the amount of oily component inthe lipid phase to the total amount of surfactant and co-surfactant inthe aqueous phase is from 0.2 to 1.0; and c) combining the lipid phasewith the aqueous phase to form an oil-in-water microemulsion in whichthe average particle size is less than 30 nm.
 27. The method of claim26, wherein: the weight/volume ratio between the amount of surfactantand co-surfactant in the lipid phase to the amount of surfactant andco-surfactant in the aqueous phase is 2.2 to 9.8, inclusive, or 2.4 to8.6, inclusive; the weight/volume ratio between the amount of oilcomponent in the lipid phase to the amount of surfactant(s) andco-surfactant(s) in the aqueous phase is from 0.22 to 0.98, inclusive orfrom 0.24 to 0.96, inclusive; in the lipid phase, the weight/volumeratio between the oily component and the surfactant(s) andco-surfactant(s) is from 0.05 to 1.4, inclusive, whereby: the sizedistribution of particles in the resulting microemulsion is 15 nm±10 nm;and the polydispersity index (PDI) is within the range 0.02-0.380,inclusive, or 0.02 to 0.2, inclusive, or 0.02 to 0.15, inclusive, or isless than 0.2 or less than 0.12 or less than 0.1.
 28. The method ofclaim 26, wherein step c) comprises titrating the lipid phase with theaqueous phase.
 29. The method of claim 26, wherein: the titration rateis described by the following equation:V _(tit) =k×(v _(tot)/1000 ml); V_(tit)=titration speed in ml×min-1, k=2ml×min-1, and V_(tot)=total volume of the formulation in ml.
 30. Amicroemulsion composition prepared by the method of claim 27.